2fa pales in comparison to 2fma, for me. I found 2fma to be basically free of side effects, yet stimulating in a way that i can workor party for up to 72 hours easily. 2fma is euphoric and gentle but has everything i'm looking for in a stim, feels pretty similar to dexedrine - for me.
2FA was more jittery and side effect ridden and i kinda ended up doing too much whenver i did 2fa trying to get high when it just wasn't there. It would make me very sweaty unlike 2fma, and just wasn't really euphoric or functional in the was that 2fma is. Also 2fa is sort of antisexual for me and 2fma is pro.
3FA was pretty similar to 2FA for me but effects were mild and i didn't find it worth a damn in any way, i never would acquire it again.
4FA is much more euphoric than either but redosing with 4fa can lead to some serious complications, doesn't really work well with redosing but is still very compulsive and will leave you very low. 2fma can be redosed and redosed with no problem, never had any bad effects when stopping.
Those are my experiences with them. If i could have any stim right now it'd be no contest, either 2fma or methamphetamine.
edit - i dont recommend 72 hour binges, i'm just stating the drugs seemingly gentle nature