Given that the release of Gabriel Knight now means GOG has at least one game using the SCI engine, and given that SCI is currently one of, if not the most active area of development in ScummVM, will games be changed over from DOSBox to ScummVM when ScummVM officialy supports them, or will they remain using DOSBox?

Simon the Sorceror 2 also uses the Scumm engine and comes with ScummVM instead DosBOX. (Many thanks again @Igor)
So I would say yes.
And of course I copied Simon over to my regular ScummVM directory and added it there, works also perfectly.
However, for Gabriel Knight it always says there is no game found so it is either not supported by ScummVM or a different version.

wut?

It's not supported by ScummVM.

GK is not supported by ScummVM yet, but probably will be in the future.

AFAIK support for Gabriel Knight is ongoing work in ScummVM, no idea how far along they are.
You can try downloading a development version and see if it does anything: http://www.scummvm.org/downloads/#SVN

I hope they don't. ScummVM is a nice enough project, don't get me wrong, but for me DOSBox is just the authentic way to do it. ScummVM is easier for DOS newbies I'm sure, but they take a lot more liberties with their games, altering the music, adding or changing elements, etc. Thanks but no thanks. Authentic > ease of use.

I'm sorry, what?

You didn't notice? They alter the game's graphics in places, they replace certain music with different versions of the music, etc. Nearly every ScummVM game I've tried received alterations.
One example: King's Quest III in ScummVM has mouse support. It doesn't in the DOS version. The PC speaker music is replaced by an adlib rendition of the song while the DOS version had no such thing.
Sure, in the scope of things it's no big deal but it's NOT an authentic experience. If the ScummVM crew can't emulate the games accurately (or at least give the option to disable these ... "enhancements" ...) then I'll stick with DOSBox, thank you very much.
It reminds me a bit of Exile, the emulator for Ultima VII. They designed their own engine that is based on the original files but the actual rules of the game changed in quite a few areas. Old exploits were gone, old combat strategies no longer worked, etc. When you add the benefits, it still made Exile well worth using over DOSBox (due to the bigger playing field mostly) but in the end, it was not an authentic experience.

What? Almost nothing is altered. The only altered graphics are in early EGA SCI games; we have dithering off by default. However, it can be enabled in the configuration file -- you can choose what you want.Is that really a problem with mouse support? Does it really bother you that something was added to help you? You can just not use the mouse. However, there is mouse support in the Amiga versions, where this is derived from. Not to mention, AGI does not have AdLib. AGI uses PcJr 4-channel sound, which was in the original.It is an authentic experience. We do, however, fix bugs that were in the originals to make the games more playable. We can't make you use ScummVM, but it definitely is a better experience that still is authentic.

What you say is all true but doesn't actually counter anything I said. You pretty much admit you make alterations: mouse support from Amiga, tweaks to the game, music from the PcJr (which was not available on any other PC), etc. (and DOSBox DOES emulate the PcJr music if you want the 4-channel sound and it's nothing like the version ScummVM uses).
Just to make clear: I didn't say it makes for a worse experience, I said it's not an authentic experience and for me that is important. Mixing different versions of the game does not make it authentic by any means. Star Control II: Ur Quan Masters is not an authentic PC version of the game either - it mixes & matches between DOS and 3DO version. It's a better game for it, but if you want to play the absolute original version, it's hardly the best choice, is it?
The thing is, you can't choose whether you want these alterations in ScummVM. AFAIK there's no way to disable the mouse cursor or to play the original PC speaker sound which most people will have heard when they played the game 20+ years ago. If I were to replay a child hood classic of mine, I would want everything to be the same and not tweaked according to your wishes with no option to disable it.
In any case, you're missing the point regardless. You think in terms of playability, I think in terms of authenticity. I even gave the example of Exile above to make that clear. In any case, I hope this clears it up. When I asked fellow retro friends, they had similar experiences of altered games by the way - it all depends on how authentic you want the game to be. That's why I don't want Impulse to use ScummVM as default.

Did you try setting the music to PC Speaker?Since the games really aren't altered, your argument doesn't hold up. Almost everything can be configured, really.

You can still use the keyboard.
To supress bugs in the game. In some games, game-stopping bugs are worked around. Don't you think that's a good idea?
You can still change the sound output to PC-Speaker.
I'll take more choices and worked around gamestate explosions over some ill-defined "authenticity" (which is a laughable term anyway, with the myriads of different hardware setups the originals ran)
...you won't want DosBox either.
You can
- Not use the mouse
- Switch to pcspk
- Switch off graphics interpolation
- Switch dithering back on
You can't
- Disable working around of game-stopping bugs
Yes, that you can't, AFAIK. But it's a very quick thing to do in the source.
Maybe worth adding a configuration flag. I don't see a feature request in the ScummVM bug tracker for that from you, though...
Wrong, you can.
The GUI option is in the Music tab, output PC Speaker (or something along these lines). The command line switch is -e pcspk
Everything? Get your old hardware out then.
Like I wrote above, given the nature of PCs (and the number of other platforms the games ran), "authenticity" is a useless term.

I'm glad to hear you can change the defaults. Don't get me wrong - I'm not attacking your software, I'm merely stating why I don't want it to become the default.
With "authentic" I meant "the way most people would have played it" although it's obviously a personal experience. In the case of King's Quest III, this is PC speaker, no mouse and EGA graphics instead of PcJr, mouse and Amiga graphics. I mean, not one of your default settings are possible on a standard IBM PC with that version of the game so it's a bit silly to then argue with me about what "authentic"' means. It obviously does not mean the default settings you have now.
For me, an avid collector, I need to be sure that the game I play is the game is what it would have been like on old hardware. Currently, ScummVM doesn't fit that bill, I'm sorry. You can hardly deny that, either. Don't forget you replaced the save menu for many games, replaced certain game elements with your own (like the "game paused" feature in LucasArts games), remove copy protection (which, for some, is part of the experience), etc.
However, for those who just want to play an old game and don't want to get into DOS or fiddle with protection wheels, it's a better option, of course - but I never said it wasn't.

Would you like ScummVM to supply you with a 14" CRT monitor as well?
Somehow, I seriously doubt that ScummVM contains alternative graphics for all the games it supports. If you've seen Amiga graphics, it's because you loaded the Amiga version of the game. If you had loaded the EGA version, you would have seen EGA graphics. ScummVM is an engine for running certain old games on, it's not a remake of any of them.