The apps run faster, stuff that used to slowdown in my netbook isn't slowing down anymore (To be honest I only tested one game, and tested it pretty quickly, but the way it was faster was very noticeable), but the compiling time is a LOT slower. It seems they are still going to update Studio on this, and they are promising in near future games running even faster, they are talking about 10x faster than now.
With GM8 I use a .DLL to handle music playing. Check out my other game Operation Gaex at
http://shatterhand.beatthgame.net
But they are promising better sound handling in a near update, with oficial OGG support, change of frequency and speed in real time, pause and resume sounds and some other stuff.
The thing is that Game Maker 8 and previous versions were made only by Mark Overmars, with some ocasional help from other people. Now Studio is being made by a team of programmers, and they are really trying to make it as professional as possible. I am really surprised, it's a lot better than I expected. There are still some minor issues, but they are updating it constantly.
The price is a bit steep though for sure, I just bought it because the school where I work actually paid me to buy it, study it and see if its interesting to use it in our classes. We already use Game Maker 8.1 lite there to introduce them to programming, but the possibility to develop for android devices made everything even more interesting from an educational point of view
I've been using Game Maker for 10 years now. I can code in Java, C#, C++ (Well, just a little bit), Basic (and Visual Basic

), Object Pascal/Delphi and PowerScript/PowerBuilder, and I still prefer to use GameMaker for game development. As I do it just for a hobby, not professionally (And now use it to teach kids how to program), I think it suits my needs perfectly, it speeds up development a lot. But with GM Studio, I have a feeling I could go semi-professional with it and do it finely if I wanted to.
Coding for Android in the traditional way can be a pain in the ass sometimes... if GM Studio proves to be stable and have a performance good enough for it, it may be an excellent way to make Android apps. And so far, it seems it can do the job nicely.