I've bought books from Jim for years, though I don't know him well. Not a place to roar through, books are piled everywhere BUT in a rational order. Abraxas will have things you've looked for for years and things you've never heard of.
The place is a treasure trove, but you really have to hunt for the book you want. And speaking of books, the store is overflowing with them--piles on the floor, spilling over shelves (of which there aren't enough). Because browsing is a very time-consuming operation in this store, I'd recommend you go only when you have a lot of time to spend. I didn't find prices marked on the books I examined, so be sure to ask the price before you buy. That said, the store is interesting and you might find some hidden treasures. This is a store for die-hard book lovers.