Knowing nothing about two exam candidates, which would you be more likely to bet on--the one who has taken multiple practice tests or the one who has studied materials only? Makes sense to be the candidate you'd bet on!
Okay, so how best to figure out which ASWB practice tests to use as you're prepping? The leanings of this site is clear (just look at the sidebar). But don't let that decide things for you. On that same side-barred site (for folks on phones: it's SWTP), there's a handy list of free practice exams. If you've got time, you can click through there to get a sense of what various companies have to offer via their free samples. And while you're at it, you're getting free licensing exam practice.
Make sure you're not just being drilled for memorizable content (e.g., "At what year does such-and-such a theory say that such-and-such a behavior begins?). Good exam items--like most on the real ASWB test--reach not only for content, but for basic, genuine social work know-how. To get at that usually takes vignette questions, which is why that's what you'll mostly be encountering on the real exam.
In any case, congratulations, you're on your way. If you're studying now, that means should all go well--and it should!--you'll be licensed soon! Good luck!
