No way is Beggars better than IOS. I probably like it more than Fire, although the first 2 tracks of Fire are brilliant.
I think my major issue with Beggars is I feel that the lyrics are too preachy and the vocals at times grate on me.
I guess a lot of this is personal preference, but TIOS (I love it, by the way. not that I dislike it or anything, I just love it less than other Thrice albums, except for IC) just doesn't feel as mature as they got post-Vheissu.
I don't mind the lyrics at all (I am a Christian, so that probably has some bearing on that; but trust me, I know and despise excessively preachy bands) but if it really bugs you, think about what Riley Breck said - the music wouldn't have so much passion if Dustin wasn't singing about what he believes in.
can totally see why you could think the vocals grate a bit - I had the same issue when I started listening to Thrice. don't mind the vocals at all now. love how skillful he became with his singing.