They're made from MDF, so they sound dead and lifeless.
Cabs are so underrated, but IMO they account for a big part of your tone (I mean the wood and construction, not even talking speakers). I was one day testing like 8 different 2x12s, all with either V30 or combo of V30 and G12H, and no two cabs sounded the same.
Prices are down everywhere, I'd rather get something good used.
If you're up for a 4x12 you should try the EVH 5153 straight cab, that thing sounds awesome. Marshalls are great, especially old ones (pre 1980s). I would definitely try them before buying, you will see what a huge difference it makes.