ORIGINAL: jester_s1
They won't really be much different. You'll find that the Super Tiger will pull verticals better for big loops and hammerheads, but it's not like there will be a drastic difference. If you were comparing a .61 to a .90 or 1.00 then there would be something to discuss.
I disagree.
There is quite a significant difference between the ST 75 and the ST 61 in terms of performance.
I have an ST .61 in a 6lb-7lb plane and the plane cannot prop hang even with a wide low pitch prop.
I have an ST 75 on a 9lb+ Big Stik .60 to which I've purposely installed heavy battery packs. This plane will prop hang, torque roll and has unlmited verticals using a 12x7 prop.
I find the ST .61 closer in performance to an OS AX .46 or so, not that it's a bad engine... but there is quite a difference between the two.