First off, for the money, it's great value. 4 Celestion V30 speakers will cost more than the cost of this cab, so it's worth that just for the speakers alone.
It's the smallest 4x12 cab I've ever purchased and that does impact the sound. It's the brightest and least bassiest 4x12 cab I've heard. A bit of EQ tweaking can sort that out, so it's not really a pro or con. The small form factor (by 4x12 standards!) is handy if you want to transport in smaller vehicles.
On the customisation side of things, mine was a very tricky to get the back off. The back was really jammed in tight and it took a look of prying, all around the edges, and I had to take a side handle off to push from the inside to finally unjar it. It almost felt like it was glued in, but it wasn't.
If you do take the back off, be very careful. It's also best to take the jack plate off. It looks like an accountant decided how long the wire should be and not the person building it! It's very easy to pull the back off and yank the connections off, as they are very short wires, in comparison to a Marshall cab where you have several more inches of wire. Inside, the speakers are bolted in, instead of being just screwed, which a lot of people consider a good thing.
Mine was delivered to the UK and, unfortunately, suffered a bit off damage in transit. I decided to take a partial refund, as it took a couple of whacks and tore the tolex in a couple of spots. It looked more like B-stock, when it arrived.
In case anyone is wondering, the cab is built with 4 x 16 ohm speakers.
All in all, I'm happy with it.