The Gen8 has a socket 1155 unlike the older Gen7 that has 3/4 soldered options iirc.
Mine did come with the Celeron G1610T which I then swapped out for an i3-3220T then finally the E3-1260L..
Having had the Gen7 and the Gen8, I do prefer the Gen8, its a nicer chassis to work on and although it only has 1 expansion slot on it I found that the 2 I had added to my Gen7 (USB3 and second NIC) are built into the Gen8 so I also added a P222 to give me more grunt..
The main failing of the Gen8, imho, is the gap between the heatsink and the drive cage, makes cooling an issue, and the fact that its limited to 16Gb RAM... the first of those issues has been almost addressed by the new SKU's that were released with a revised heatsink but the 16Gb of RAM is a PITA as I've got 5 VM's that run on mine and rather than leaving them all on I have to shuffle them around and keep an eye on the RAM...
Its looking less and less likely there will be a Gen9 so I might be leaving the Gen8 brigade, stripping it for parts and building something bigger with more expandability that will then go up in the attic...