I have an Aiptek Action HD-GVS. It can do 1080p (1440x1080) @ 30fps but at that resolution there are bad distortions in track videos. I think it has to do with the sensor/shutter architecture? Anyway, video quality is much better at 720 60fps. It still shakes quite a bit on track though. The reason is the tripod mount in the bottom of the case has nothing but plastic around it, so no matter how solid your mount is, the camera itself still flexes like crazy. I'm in the process of building a "cage" to surround and stabilize the camera using a metal outlet box that will be cut/ground to fit and then padded where necessary.
One of the reasons I bought that specific model is that it has a mic in jack. Most other Aipteks don't and the internal mics suck. On track you will hear nothing but distortion even with a stock engine and stock exhaust. I built a set of 9V-powered mics using Linkwitz-modded Panasonic electret capsules (google that **** if you want to build your own) and it sounds great, when I remember to plug them in.
One thing this model cannot do is act as a DVR, so you cannot record using a separate video source into the A/V jack. Other Aipteks can.
The PITA for me is trying to do anything with the video files it creates. Not only do you have to monkey with the files a bit, but none of my computers has anything faster than a single core 2.0 GHz processor, and 30 minute track sessions recording at 720 60fps creates some large files.
Anyway, I think the Aiptek is "okay" but some effort is required on your part to make it a good track cam IMO. The tradeoff is that it's cheap.