All righty then, here's a quick summary for each character in combat:
Miles Morales:
The "Thief" Archetype. He is just as strong as Parker but less weight behind his punches mostly due to his smaller size, also means he's faster. Has a adaptive camouflage ability along with his 'Venom Strike/ Poke'. He requires skin contact to pull that one off though. But based off a few sources, under intense physical stress (torture) he can unleash a 'Venom Blast' from his body, but it creates a really bad EMP effect on all electronics in a city block.
The trade off is that his Spider-Sense isn't as strong compared to everyone else. It comes off as more off a buzz in his head.
Jessica Drew:
Generally the same powerset as any Spiders, the only difference is that her webs are organic and they shoot from her fingertips. Also, really good detective. Her downsides are mostly the clone complex and her tendency to go Cowboy Cop. She did end up leading the New Ultimates though, so that's something. Deputized by SHIELD as well.
Spider Gwen:
Same Spidey template, but from what I've read in her stories, she tends to unwittingly tank hits instead of dodging them. Prone to impulsive actions like any teenager her age. Uses her drumming skills to pound tougher foes (Rhino). Her webshooters surprisingly, are not built by her or Peter. Apparently, it was a gift from Janet Van Dyne when she retired. It works by drawing in moisture from the air and converting it to the 'webs' she uses.
Miguel O' Hara:
Mostly the same Spider Package but with a few extras. No Spider Sense for Miguel instead a "Enhanced Perceptions" that tune in to what's happening around him very quickly such as immediate danger or a general Plot Point. Still has limitations like what is he focused on, can be caught flat-footed. Has retractable talons on his fingers and toes (uses that to wall crawl). Webs are also organic and chemically identical to real Spider-Silk.
That's quick version of the four choices available. If you need further clarification, try out the Marvel wiki page. And er, votes will be locked in about two or three hours from now. Update will be later tonight.