APM 2.0 has the latest sensors (gyro, barometer, accelerometers), better internal wiring, better future support from a firmware base, is smaller, and just a revision of the APM 1.0. One plus is all the sensors are digital and thus noise is far less of a problem. Again, APM 2.0 is just a very good revision with the latest sensors and a couple of better features. THe kicker is the new APM 2.0 is cheaper than the old APM 1.
APM 1.0 with oilpan is good and does everything APM2.0 does. It has a barometer that is slightly less sensitive, it uses analog sensors and then a digital to analog converter chip to read the anolog sensors. The GPS module is always external, and the kit comes with the magnetometer (AKA compass) which is a built in feature of APM 2.0.
There are one or two things not yet compatible with APM2.0
Optical flow-basically taking an optical mouse sensor instead of using sonar
The spektrum satellite reciever adapter (This whole idea is really for super lightweight indoor quads because you are using the smaller Spektrum module which in theory has less range and features). Being APM2.0 is lighter and smaller than APM1.0, just use the full radio reciever and it doesn't matter.
Neither of these is considered a great loss and optical flow is very experimental.
The following sensors are optional and work 100% with either APM
Airspeed-mainly for planes, not so much helis
The bottom line is APM2.0 is better in every respect, has the same basic sensors (better versions though), works with all the important sensors, should one day work with the expermental sensors/adapters. It has a smaller lighter footprint, no soldering, no fuss just plug it in and use it. It's also an amazing $200.
The older APM 1.0 costs $249 the last time I checked, has older analog sensors, and required good soldering skills to assemble. The only gotcha is the optical flow sensor works with this board but not APM2.0. Again, that's not a reason for me to recommend APM 1.0 over 2.0.
How can I say 'thank you' for such a detailed answer ... thanks!!!!
I already thought so but couldn't really read it 'between the lines', the price kinda irritated me and kept me thinking that there might be something to the ArduPilot Mega Kit that the APM2.0 doesn't have ... now it's clear and the only thing that is left is waiting until it is available in the store ... :)
At the rate they have been shipping, just order it as the pre-order unless they pulled that option down. Honestly, I was worried too on my last APM 2.0 order but it came up much faster than the previously annouced wait times. They are cranking them out as fast as possible.
Yep, still the same old tired 8-bit processor. Since they off load the PWM and some other communication features to the 2nd processor it's almost like having a 16-bit processor. Hopefully the dev team is hard at work porting code to one of the more modern, and cheaper, 32-bit processors. IMHO it's not worth waiting for that to happen since the APM2 is pretty cool despite a few problems it has, and it has just enough power to do most things you can think of.
Wondering when we will see the first ARM version ;)