Functionally, they are the same. The Peak Model 1 shows an angle of 30 degrees while the Peak 2 shows 20 degrees. The additional 10 degrees is gained by swiveling the optics over a longer mirror. This provides more coverage than the Peak 2 for extreme angles in corners. Additionally, replacement mirrors are available for the 1. My 2 has replacement mirror on the bottom, but with care I still have the original top mirror.
I have used both. The metal frame on my 1 broke when I knocked it to the concrete floor. I have used a 2 now for about 7-8 years. I think the optics are slightly better on the 2. All 3 can use the blue filter eyepiece, which to, me did not make a difference.
No one that has used a Peak 2 would put it in the same class as "any run-of-the-mill grain focuser". The Peaks, either 1,2 or 3 are significantly better tools.
Only the Microsight comes near.
You will have a first class tool with either one. Budget dictates the choice.
Cheers,
Geary