Well, over the years, I have had two combos (Drome gen 1 and Classic 60, both without leakage etc), as well as ProLine 210 (2 pcs), 410, 15F and 311 + NeoLine 212. They spanned at least a decade of production, all with a consistent "budget" execution.
As for deep bass, EBS seem honest about the ProLine specs, and the 410 is spec:ed to roll off around 70 Hz, and that seems about right.
Since years, I use Ampeg SVT-410HLF, which starts rolling off in the mid 40s. I have longer ports in mine, extending the bass below that, at the expense of sensitivity. It goes deep and loud even with my active five string, FAR beyond the point where my EBS cabs were choking, compressing and farting out.
The only cab from EBS that approaches the HLF for deep, loud bass is probably the NeoLine 410. About twice the price, and I assume (right or wrong) that it still leaks, lacks bracing etc.
EBS cabs are articulate, with maybe the best tweeter I have heard in a bass cab, and they are robust and easy to handle. (I think they have a unique, cool look, too.) The shortcomings in manufacturing can be corrected with time and effort. For deep, loud bass, other brands will give you far more for your money. It is not even an opinion, just a fact.