I would probably vote for m18, as I've heard so many good things about it.

I own a mini-t(actually a mini baja). The electronics were junk(everything including the motor died within 1 1/2 years) and the stock diffs don't hold up well to brushless power. Also the stock steering setup introduces slop over time and use. It's a fun car, but considering the cost to get it set up decently, you'd be better off paying more for a better car

The mini lst had a poor drivetrain(notice I say "had", it has been discontinued).

The rc18 t2 or b2 have problems with steering slop and drive belt rubbing(Foxy has a thread about it).

I haven't heard of many problems with the rc18(original) or the vendetta, so those would probably be decent choices.