Disclaimer: It's not a scientific article. This post inludes some subjective observations and sarcastic remarks. If you cannot stomach it, stay away instead of flaming me.
I. UB. Two distinct subtypes: (1) about 90% are rude arrogant egotistic semi-noobs that have no map awareness, play no other DG, and are allergic to words like 'strategy' and 'tactics' (they just Spit > click on target, so why bother?) -- these guys usually play BotF Spit/Ooze hybrid (though I've seen BotS players that fall into this category, too); (2) a small caste of elite UB players, that are usually quite intelligent (they can actually talk, ffs!), and play this game mathematically -- they understand playing a very good UB is hard and requires precision and flawless calculations. E. g.: Zen_God can be a nice example, though he cheats on his UB with a speed Rook! Hah!
II. Oak. Well, this is the most annoying player type, in my opinion. Oak is easy to abuse. Too many 'gay' tactics, too many half-exploits. Also, his skill set is as close to perfection as it gets. It draws a certain type of players, to be sure. Independent of personal skill level, I think I've never seen a dedicated Oak player (= a guy that mains Oak, not just plays him) that wasn't in his asshole mode at least 50% of the time. E. g.: Think Wip_ or MacLoover.
III. Rook. The exact opposite. I love these guys. Usually quite phlegmatic and cold-blooded. That's why Zen plays speed Rook, I guess 
Seriously, they are all somehow restrained, or at least take it easy. E. g.: I suspect (not sure, let's see if my typology works practically) Cow is one of those guys originally. Ppapanek is also a good example.
IV. Erebus. An interesting type. I think dedicated Erbs are the most personally skilled of all top-tier DG players, perhaps because he requires heavy microing and precise Mist timings. The best of those guys are somewhat similar to an 'elite UB' sub-type. Mathematical precision and intelligent judgment. E. g.: Maybe Renz can serve as an example, though he doesn't play much Erb these days, I think.
V. Sedna. I'll try to be objective here. Sedna draws a certain type of crowd... Let's say, people that love to play their game a bit too intelligently. Thorough (sometimes, too thorough) people with great love for theory and numbers. But the fact is, I've never seen a dumb player that mains (or even plays!) Sedna. She's just that kind of DG, probably. E. g.: Hedgie, of course.
VI. QoT. QoTists are similar to Sednaists, but usually a bit more excentric. Maybe it's even the same type, I don't know. Let's just say, dedicated QoTs and Sednas are hugely different from the rest of the crowd. We should also mention their towering intellect, blah-blah-blah... 
E. g.: LORD-ORION.
VII. TB. A strange crowd. Two distinct sub-types again, very similar to those I've mentioned while analazying UBs: (1) Fire TB players are not as bad as non-elite UBs, but probably close second -- maybe because playing a Fire TB is so ridiculously easy. In short, they don't strike me as intelligent or nice people at all! A player playing a DG with high damage and speed, but very low hp and no freaking interrupt clearly has... issues. Oh, they are also dead conservative, always stack speed and never switch forms. They also tend to type a lot into All chat. Haha, take this, Pacov! 
(2) Hybrid or Ice TB players. They are great. Smart, skilled, polite players not afraid of trying new things/setups/builds. E. g.: Think of Thundercles. Think of him, goddamit!
VIII. Occ. Honestly, I don't like Occ players. Occ is one of the, or maybe THE, most primitive DGs to play. As long as you don't overextend horribly when oom, and target your butt-jumps/chain lightnings/exploding balls to any point roughly within 20 y radius (= aren't totally blind) to hit everyone for 65765675 damage -- congrats, you may consider yourself a solid Occ. No precision required, no creative thinking involved (no reason to think, as most of his skills don't work w/o Uberfix). How can you get excited about such a character is a mystery to me. E. g.: While I can think of some good examples, I won't post them here.
IX-X. Reg & DA. (1) Kill-happy n00bz, or (2) players so old and tired of this game, they prefer to handicap themselves either for early (DA) or for late (Reg) game. E. g.: The only serious player that mains Reg is Darkliath. She claims she's just not so good with other DGs, but I suspect she's simply tired of playing upper-tier DGs and dearly loves challenge (look at her win % and compare it to her skill).
