I was a very avid Savage 1 player back when it was relevant, ended up in a few competitive clans and even ended up an admin on the duel server and the more populated servers, as well as admined for the clan ladders.
I didn't get into the Savage 2 beta when it came out, but a bunch of my Savage 1 friends did and they all basically told me "It's not as good or skill-based as Savage 1, but it's fun I guess." Which basically made me not play it. However, it's supposedly free now (except I think you still need a premium account for something?), so couldn't hurt giving it a try since I'm on a pretty tight budget.
Will it just bother me that Savage 1 ended up being better, or will Savage 2 make me happy and end up better? And if I'm not getting a premium account, what am I missing?
For the hellborne thing it is limited to 1 time unless you have the prime, that is 1 time for each hellborne. This lets you get a feel for it and while not entirely necessary it is still useful.
As for is the game worth playing... I certainly think so. When you ultimately do get a feel for the battles and strategy the game becomes a lot more fun. Taking on 3 people at once and coming out victorious on numerous occasions will make you absolutely hooked. Plus if you do have the prime kicking butt pays well with the malph or devourer(the ranged guy kinda sucks imo) which in turn leads to holding off assaults single handedly or just going buckwild on everyone. The better you do the more fun it is and the block system is useful and strategic while giving some leeway.