I dive Dry. I have dove wet, and I can say, I will probably dive dry in the summer.
I did my OW in a 7mm 2pc in September. I was comfortable, but it was still very warm topside. I think the benefit of a drysuit is when the water is comfortable, but the topside is cold and icky (typical in the Spring and Fall). When you get out of the water in a drysuit, other than your hair and hands, you body (core) is dry. The outside temps are not as shocking to your system. You may be warm in the water in a 7mm, but when you exit in 60 cloudy weather, brrrrrrrrrr. Have lots of warm and dry towels nearby and the ability to add warm water to your suit to warm up.
I bought my drysuit used through my LDS at a really great savings. If you check out the WTS forum in SB, you will find MANY people selling drysuits and at very good savings. There is nothing wrong with buying used. If you buy used through an LDS, ask for new seals in the deal. If you buy through the forum, expect new seals, <$100 in most cases.
Also, check out the quarries for the drysuit demo days. I can't remember the details, maybe someone else will post...
But DUI has a demo day at Gilboa, and I think White's will be at WhiteStar. I'm probably wrong, and I'm sure Portage has a drysuit demo also. You can try out different drysuits this way.
You may also want to consider taking the PADI drysuit speciality (even if you don't own your own suit). I believe LDS' will rent you a drysuit if you have the specialty card. Then, if conditions are optimum for a drysuit you can rent one.
I think you really need to identify when and how often you think you will dive outside of the summer months (May - October). If you are considering doing early spring and late fall diving, a drysuit is a good investment. I have done winter diving in my drysuit and have become hooked on the conditions. Next year I will do my ice course.
In September, when I took my OW, if someone suggested I would be diving in January I would have scoffed. Under ice - no way. The drysuit however, has opened the opportunities to me.
Good luck.