Disclaimer: I don't use a dry suit. I was just stuck by a logical issue with this point; no matter how many wet suits you could buy for the price of the dry suit, you will only wear one suit at any given time when you dive. So while the cost vs. benefit question is valid, the issue of how many wet suits you can get with that money doesn't matter, unless you are assuming the dry suit will wear out, and thus the wet suits would give you much longer service. Otherwise, the issue is whether one dry suit will give you worthwhile advantage over the one wet suit you'd be wearing on your dives.
So, some questions to maybe help the dry suit divers help you.
1.) If you had the dry suit, would you just be doing the same dives, or would you be doing some dives you wouldn't otherwise do (e.g.: winter, colder locations, etc...)?
2.) Is being dry just a novelty you're curious about, or does it offer you a practical benefit?
3.) You said you know the pro.s, but have you trained to use and rented one to try out a few dives in? If you're on the fence with 'head knowledge,' perhaps diving one a few times would provide the swing vote?
Richard.