I've developed an application called BoomBoxoid, which is an mp3 music player. It has already been published on the market, but I get complaints from some users stating that it is very laggy on their devices, specifically mid to low spec devices I'm guessing.
It was developed and mostly tested on HTC hero and Desire, runs great on the Desire and decent on the Hero, sometimes a little lag here and there but not enough to make the app unusable, but thats just my experience. Anyway I'm not in a position (almost impossible) to be able to test on all android devices out at the moment so if some of you kind people could help out with some beta testing I would be very grateful. Ideally I would like some beta testers with mid range devices such as HTC Hero, Tatoo, Samsung Moment, Droid Eris, G1 etc. Some testing on higher range (Nexus, Moto Droid) devices are welcome as well.
The app is available on the market, just do a search for BoomBoxoid. Theres a free version and also a premium and pro version with additional features. Thanks in advance for all your feedback, I'm looking foward to it.