First, whether you buy it through Steam or direct on the EA App, it will be played via the EA App. So no getting around that.
All I can give you on which is better is anecdotal. I've been on this forum for years and it seems to me that there are substantially more problems playing with the Steam version (usually licensing issues, though this happens direct as well). Again, that is anecdotal. But really, any personal reply you get will be a single data point (essentially, an anecdote).
So my view: why buy it on Steam when all it does is add an extra layer to go wrong? (unless it is cheaper, or you just love the interface/XP/whatever)
Last: if $ matter to you, wait for a sale, which happens often. I got it with a one month Humble Bundle sub. It was free on Prime Gaming for a while. And I've seen it on sale for $5-6 at time.
I don't want to discourage you from playing. It's my favorite series of all time and have countless hours in all versions.
