I have an Ampeg SVT48HE, which is a 4x8+tweet closed cab. Its a really sweet sounding cab. (Although I replaced all the drivers as the stock Polycone/rubber surround original drivers were only 200W. I blew one cranking my carvin, so I actually just replaced them all with MCM Chinese 8"s that were rated higher. Now it plays LOUD, can handle 300W program, and is great single cab for low to moderate volume gigs.) Be aware, 8"s on their own cannot generate super low frequencies, and that has been the complaint of many small driver naysayers. SWR Henry cabs used huge front ports for the lower frequencies, but a 2x8 or 4x8 generally need a 2nd cab to go below 45Khz. Ideally, 8's are great as top end/full range of a BiAmp rig. That way you can run them in the sweet spot, and leave the heavy lifting of woof below 45K to a 2nd cab. Just don't expect room shattering lows from 8's.
Another great cab that has 8's is the Ampeg PR1528HE. Its got a down angled 15" + (2) 8's+horn, and is, again, BiAmp-able. But that 15 takes care of the woof, and you have a single cab that provides (2) 8's of clear punchy signal.
In regard to 4x10 vs (?)x8's...different animals altogether. 10's can create lower frequencies than 8's and if your running a full range signal (read: not biAmp, single cab, single head) many times 10's are more effective. Depends are your gigging requirements, weight of cab tolerance, and your ears. Personally, I love that SVT48HE..its a great practice cab, great for lower volume gigs where I don't care about having super low frequencies, and is 63lbs, with 4 casters. easy enough to move myself. And I like the sound of it WAY better than any 10" cans Ive ever owned/heard. IMHO.
Go 8's!!