Well, perhaps it is an afterthought for some people, but for some other folks, the
FIRST thing to look at is your connection speed/capability, at least
IF this NIC is gonna be the one that you will be using to connect to the internet or your router...
If you only have 1GB service from your ISP and/or a 1GB router, then buying a 2.5G card will be useless and a waste of money, unless you are also planning/capable of upgrading to faster service & router sometime soon...
Of course, if you will be using this NIC to connect 2 computers together, then both will need the same speed cards....
But more to the point, I NEVER go with the cheapest parts, regardless of brand or type....cause as we all know:
"Cheap is as Cheap does"
I'm not saying you need to buy the most uber-expensive one either, but usually somewhere in the middle will suit almost any average, everyday user.....