8v8 (and Frontlines) are a much better place to get a bearing on your PvP abilities. It's not even close. Having less impact on the game (or more downtime between fights, in Frontline's case) gives you better opportunities to read tooltips, observe, and ask questions.
If you have no idea what you're doing at all in a pvp context, throwing yourself right into the highest difficulty is an awful way to learn. It's like trying to learn a brand new class (at 50/60) by trying to do EX primals rather than EX roulette.
