are to be recommended IF you are buying them from the Apple Store.
Those machine has been refurbished by Apple and carry a full years warranty and are eligible for AppleCare extended warranty.
As for the processors, the i7 is the top one right now, at least in iMacs, with the quad core being up there with the winners.
As you do not mention what the price difference is, it is not really possible to say whether the 2.3 is worth the difference.
Suffice it to say, if both processors are the i7, then the 2.3 machine will be a tad faster of the two
P
am looking to buy a refurbished macbook pro and am not literate on the apple systems.
1. what is the opinions of buying refurbished computers
2. what is gained between the quad core intel I7 2.2 ghz
and the 2.3 ghz. is the 2.3 gaining that much for the price difference. should I better of looking at a 2.4 or 2.5 ghz processor?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic