Using pecuniary analysis, I'd suggest sniping a RR or PL box or both on ebay (both of which, if you try and you know what you're doing, you can get for 60-70 dollars). PA is still very expensive due to high demand, so I'd just wait it out a bit, but it's an OK set. SV just blows unless you're a collector. In that case, the artwork is pretty nice and I'm pretty sure the pull ratio is 4 lv. x per box, which is excellent.
Supreme Victors is a TERRIBLE set. You get the worst Rares in the entire universe, and there are only...about...3? 4? good cards in the entire set. Good luck.
Arceus has some decent LV. Xs, but more importantly, it's just a fun set to collect overall. :]
But, seriously, go with Rising Rivals if you can't decide. You have Luxray GL LV.X, Infernape 4 LV.X, the Rotom and Pikachu Secret Rares, and best of all, Espeon 4.
Well, I'm currently focusing on buying PA packs and having a good time with it. Got 2 LV Xs and 6 Arceus so far along with rares like Spiritomb, Charizard, Toxicroak etc. So, yeah. Thanks for all the replies so far.