Just tried a few slightly more demanding games on ScummVM, namely CoMI, Toonstruck and BrokenSword1... it went a lot better than I expected, but still, they don't play as well as the low-res games.
For CoMI and Toonstruck I used the CD versions, with CoMI SAN and BUN files compressed to OGG through ScummVMTools. Toonstruck worked without recompressing the video, which was a bit of a surprise, since I thought the ScummVM team had decided against including their own SMACKER video player. It stutters a bit during the Virgin logo sequence, since the bitrate there is ridiculously high, but otherwise performs quite well. The CoMI videos likewise stutter a bit from time to time, but nothing serious. BrokenSword1 is from GOG and already has all content in a ScummVM-friendly format, except that I had to convert the videos' sound from FLAC to OGG, since FLAC is not yet supported on Android.
The actual gameplay stutters from time to time with Toonstruck, when the background contains big animations, but again: nothing too serious. CoMI and BrokenSword on the other hand don't have any issues.
A bigger problem are the controls: Broken Sword works perfectly, but Toonstruck needs a longer click than what ScummVM/Android usually emulates and CoMI requires you to hold the mouse button to select an action. In both cases, using a double-tap (which emulates press-and-hold) solves the issue, but it's not nearly as comfortable as the single press you use in the other games.
