I'd get the 02.
Solves some problems of the 01 design (cylinder volume to barrel ratio, 90° sears and the pin is kept in place by a screw rather than friction).
Cylinder is trash, upgrade to a steel one with welded pins.
Some small upgrades are removing the stupid safety sear, the cocking indicator (neat feature for a stock gun but it's not well designed) and the already mentioned hop adjustment wheel.
Other than that, it's a solid gun for the price. Mine shoots like a laser with the stock hop/barrel combo.