Guild Wars 2

So when I look at Rare and Exotic Items, most of the time it’s only a 5-8 stat difference, is that a lot?

the difference is more than that on Lv.80 gear, for example:

Rare:
http://www.gw2db.com/items/71238-apothecarys-gladiator-chestplate

Exotic:
http://www.gw2db.com/items/71235-apothecarys-draconic-coat

If your asking if its worth it to switch from Rare to Exotic then Yes it is

well if you go full rare to full exotic you gain a total of 102 to major and 75 minor stat.

Its not a great deal I have to admit but once your 80 theres not much reason not to work on exotics for that little gain.

It depends. Are you 80 already? Then you should be wearing greens and working on rares or exotics. If you’re still leveling, don’t worry about it.

At level 80, it does make a difference. My survivability went up a noticeable amount when I got some exotic armor. That said, there’s no reason you can’t complete content in rare armor. It’s just not a lot of fun sometimes because you’ll die more often, and other people will be irritated because they’re making assumptions about your gear instead of asking. Green armor really isn’t sustainable at 80 unless you are super-awesomely skilled, or are playing a guardian.

I have seen rares that have better stats than exotics. I have also seen lvl 76-78 that are much better and cheaper but the downside is you can’t put a lvl 80 jewel or what ever into the slots.
So it’s a matter of choice after comparing them side byside.

All items of the same level and rarity have the same stats. They aren’t random or with in range like some games. http://wiki.guildwars2.com/wiki/Item_nomenclature is a useful read. A lower level exotic might be better than a higher level rare. With a level, better rarity is better. Within a rarity, better level is better.