I'd say controlled...because that's how I did it. ;f
Seriously, I think it is. I started in '75 at HWD (SF Bay Area) adjacent and under OAK class C (then TRSA) and under SFO class B (then TCA). Initial "other airport" training would always be stuff you had to transition 3 towers to get to.
Learning uncontrolled later was easy. On the other hand, uncontrolled (especially busy, uncontrolled) requires even more finesse and judgement. You know, now that I really think about it, I dunno. ;d
Next question, please! ;f