I'm now of the opinion that it is at least as good as Vitalogy - which is probably my favourite Pearl Jam album to date.
Vitology was a dark, dark album! Took me a while to really get into it and felt a little disappointed at first, but I think that was partly due to the huge shadow that Vs cast. Vitology is not not exactly an easy listen, but on reflection its defo one of their best.
Its hard to compare that album to their newest one though as my life (and subsequently my musical tatste) is vastly different to what it was in the early to mid 90's. I would have to say that Vitology is probably better for me overall as it was more relevent and all encompassing than "Pearl Jam" is for me today. Defo would say there are similarities between the two records.
Nothing comes remotely close to Vs though. Its simply one of the finest albums I have ever purchased and rocks from start to finish. If you wanted a candiate for a band who blew away the "tricky second album" theory then Pearl Jams "Vs" does it for me.
Did they ever better this? No for me.