The only similarity between BB10 and BB15 that I can make out are the curved walls in their house designs.
Other than that, they're nothing alike whatsoever. BB15 was an ugly, convoluted series with a cast that was just as unpleasant as the production that year and even though I don't rate BB10 that highly at all, it's nowhere near the same league of awfulness as BB15. BB10 was just meh for me - I don't love it, but I don't particularly hate it either. I just found it quite flat and depressing at the time, but then again I haven't seen it since it originally aired.