It's very action filled. You are managing casting and resources in real time with active dodge, block, and cc breaks.

Well there is some armor and skill lines to be had. I would say it's less profitable on average than PvE. People mainly do it because they enjoy PvP, and ESO's is overall a lot of fun even taking into account broken skills and lag.

The Cyrodiil campaigns run 24/7. You can pretty much jump in and out how you like. Though off-hours when there is little action or peak hours when there may be a queue to get in and lag should be considered.

Also, you'll find plenty of action in any of the full campaigns

Good if you enjoy one shot pew pew playstyle and bad if you enjoy more sustained and deep tactical combat. Numbers = win, burst builds = win

1) Feast or famine usually. When it's dead it's dead, and when there is action there are zergs. It's open-world AvA, not a PvP game, and it's advantageous for players to clump together and take out objectives. It's never "fair," but it IS fun sometimes if you can deal with that model.

2) Aside from personal satisfaction, you gain XP and Alliance Points, neither which matter overly much compared to other forms of advancement. Do not count on pure PvP for advancement, basically. Luckily, the PvE is fun.

3) Very easy. However, the disparity between a lowbie and a vet in the same Campaign is huge even with the scaling. Luckily (or not) if you tag along with a zerg you have a lot of leeway to adopt strategies (front line support, pushing the line, area denial, neutralizing flankers, etc.) You can learn a lot by dialing it back and supporting the vets, tbh. Which I think is cool.

It's a PvE + PvP game, and the two approaches are tied together. It's also not a competitive PvP game like many others, but a broader-scale mishmash. Basically it's what you make it. If you are coming from an arena-based competitive game looking for something similar, you won't find anything resembling that here, though.

It's a MMORPG that has a PvP aspect. Both aspects are affected by the other.

Blackwater blade> every other campaign.

in all seriousness, it is filled with a lot of action, depending on chosen campaign. some campaigns are filled with action, others are deserted empty husks.

rewards? in all honesty, there is only one reward that is worth taking to PvE, which is a PvP earned ability known as vigor, one of the only two effective stamina heals in the game. If you are a mana build then unless you want proximity detonation, there is no reward. You do it because you like to do it.
It is not hard to get into it, thee is a "you cannot have characters of opposing factions on the same campaign" lockout mechanic, but that can easily be broken thru via traveling to a friend/guildie in that campaign.

It's a mess with short periods of fun.

I play Heroes a bit and it seems like the matchmaking has been improving recently after a very rough patch.