This is a pretty good comprehensive guide on wetsuits in general:
COMPLETE WETSUIT GUIDE - 360Guide
There's no difference between sizing, weight, and construction of surf & dive suits (although there are MANY different options to choose from, usually reflecting in the final price) - they may just have some different features.
In some light of it, a surfer moves around a LOT whereas divers try to maintain the same position (for the most part). Therefore a surfer would have a greater desire for a super stretchy suit that's easy to move in. They also get banged up a lot more than us divers, so they might want some extra padding/protection (knee pads, elbow pads (etc.) and a more rubbery chest to help stay on the board as well. I think the seals are also a little more important when surfing because with all the movement, it can be easy for water to come in through the neck, wrists, ankles, and zipper. Besides surfers also dealing with cold water, they have to put up with the windy topside conditions as well.
It is my opinion that the surf industry leads the way when in comes to design philosophy and technology in wetsuits - mostly because they have a greater consumer base and in general needs a more demanding suit.
All in all, the most important thing is that the suit fits. Neoprene is neoprene and stitching is stiching. I guarantee most of the material all the companies use probably come from the same few warehouses in china. Also consider the conditions you'll be diving in. The super stretchy neoprene offers a great fit (which means better warmth and easy movement) but it also known to compress quicker and easier at great depth. If you're a frequent deep diver, this may pose an issue. Other than that issue, I can't really think of anything that differentiates a surf suit to a dive suit. You could use either one. Find one with the features you want, fits good, and looks good on ya, and you can't go wrong.
As for reccomendations of the best brands, thickness, stitching, zipper style, etc. etc., it really is all personal preferance. One person may get colder than you, one may prefer a 2 piece vs the 1 piece, attached hood or no hood, blah blah blah. And since conditions always change or you may travel around, multiple suits will probably be needed anyway. My best advice to you is to go to a store and try a ton on until you know what is comfortable for you.
Things like 3/2, 5/3, etc. just means that the core of the suit (body) is thicker than the limbs. With a 5/3 suit for example, the core would be 5mm thick and the limbs 3mm. It's most important to keep your core warm, and the thinner limbs allow for better movement. This all has to do with personal preference as well.
Lastly, welcome to ScubaBoard!!