chuci,
i got a scotts. whoever told you it's a PITA to install probably did it wrong. yes, you get some lock tite on your fingers when you put those screws on. yes, the small screws require a tad of patience. other than that, it's easy. can be done in 1/2 hour or less.
you'll need a 30mm (or was that 31 or 32mm) and a torque wrench for the steering bolt. else, it's easy. just be patient and be carefull on the really small bolts that hold the dampener to the TC mount, else they'll fall into the fairing and you'll have to order them. you'll definitely need locktite on those cuz mine almost fell off when i didn't the 1st time installing it and had to order replacement bolts (doh!).
if ya need help, lemme know. installation between F4 and F4i shouldn't be that different.
on the recommendation note, the brands you and others mentioned are fine. one other aspect is how must adjustment can be done on the piston types. my scotts goes up to 24 different settings.
the other deciding factor is how they hold up in a crash. my rotary one held just find in my slow speed lowside at t-hill 2 wks ago. i dunno how the piston types hold. most peeps at cbrworld prefer the rotary type for ability to hold and not break in a crash.
both types, piston or rotary, will need revalving over time. but i've heard piston types need more frequent revalving also, hence my choice on the rotary (plus an awesome price from a group by in the r6messagenet board!).