I mentioned in a previous post that we plan to make ArduPilot compatible with both 1Hz and 5Hz GPS modules. The problem is that the 1Hz EM406 that we're currently using is a 5v device and all the 5Hz devices we're looking at are 3.3v. So to be compatible with both, we'll have to put a power regulator on the board (right now it just uses the RC receiver as its power supply), and that will delay us another month for board fabrication and testing.
So my question is: how important is 5Hz to you? Plenty of other autopilots, such as the Picipilot, get along fine with 1Hz, and it seems it really only determines how tight your patterns are.
ArduPilot Pro will come with a 5Hz GPS built in, but I'm tempted to leave ArduPilot as it is with the EM406, and keep it true to its basic roots for the first version, at least, for the sake of getting it out there sooner rather than later. What do you think?