This will be our 11th season with the same Prodigy brake controller, in 4 different tow vehicles, towing our previous 3000 lbs popup, and our current 5000 lbs hybrid. It's the original Prodigy, before they started using the P2 and P3 designations.
The P2 is basically the original Prodigy, but I think it works with more systems, including electo-hydraulic. P3 is the same functional unit as the P2, but with a more user-friendly interface. That simply means the LCD screen uses actual words for functions and diagnostics, vs the Prodigy/P2 which uses a digital display and dots for functions an diags. P3 also lets you change color of display, but it functions no better than P2.
Primus is said to use the same guts as the P2 and P3, but IIRC, it is not self-leveling.
Like someone else stated, I think the P2 is the best bang-for-the-buck. If you have another $20-30, get the P3 for some bling and ease of use.
thebrakeman ('70), DW ('71), DD ('99), DD ('01), DD ('05)
2004 Surveyor SV261T (UltraLite Bunkhouse Hybrid)
2006 Mercury Mountaineer V8 AWD Premier
Equal-i-zer WDH (10k), Prodigy Brake Controller