Seems to be a straight fight between this and MegaSquirt, notice the Vems does sequential injection where the megasquirt only does batch firing (can alternate between 2 pairs of injectors though). I`d have a good look into the support side of things as well www.msefi.com is a mine of info for MS, make sure you can find similar for the Vems (you will need it ).
Vems is actually an offshoot of megasquirt, it started out as MS-AVR which was just MS on a different (more powerful) processor. It looks to be very good, all the features of MS'n'S-Extra and then some, plus more resolution, all in a prebuilt package. Website is a pig to get around though, and AFAIK their tuning interface is still a hacked up older version of Megatune, although that may have changed since I last loooked.
