Epi SG or LP 100?

also, does the 310 sg has bad neck? :?

Depends on what you mean by "bad". If you're talking about SG's being neck heavy, yes that's true.

SG necks also break easily when dropped. It's not that the neck is bad, just the problem with a thin solid body guitar with an angled neck. So, don't drop it and get strap locks and a stand.
Can't tell you which to buy, but it's probably best to get the best you can reasonably affford. Upgrading guitars is typically more expensive than buying them with the goods. You also might get other slight quality upgrades with the upper model. I don't know these guitars enough to say that this is true.
If you just don't have the money, just check the guitar out well before you buy it; I've had cheap guitars that were problem free (and others that weren't).

It's not just SG's, but LP's and pretty much every guitar with an angled head stock. It's just a weak spot in the neck, and as long as you don't go around pulling a Pete Townsend you'll be OK.

You should be careful with your axe anyway.

i meant the sg 310 has a wide neck, and its painted, so itd be very hard to get around, i just read the reviews at harmony central.

Sure, if you're used to teeny tiny satin maple necks, then yes, it's a little tricky getting used to a fully finished neck. The width is a preference issue. My friend/bandmate's SG has a little wider neck than my LP, and it takes a few minutes to get comfy on it, but if you have reasonable sized hands, then it shouldn't be an issue.

edit:

I guess I should be more specific with the word "reasonable". The dude who owns the SG is about 5'6 with proprtionally sized hands, and he doesn't have any trouble with it. You don't have to be a giant.

Vintage Epi's are ugly bugly! :)