I'll throw this one out there: is the Enterprise E in particular the strongest starship in that lineage? I've always wondered if the accepted conceit that each Enterprise is bigger, better and meaner than the last one is something of a misnomer. Especially in regards to the 1701-D and 1701-E. I like to imagine that the Galaxy Class and the Sovereign Class are reasonably equally matched, albeit constructed for different mission statements and therefore with their own pros and cons. As to the OP's question...... no, IMO Vengeance is not as powerful as 24th century starships. It appears to be ultra powerful because we have only the technology of the alt-Enterprise to compare it against. But in practical terms I don't doubt it would be technologically inferior to the 24th century ships. Having said that..... it's clear that Admiral Marcus has "pimped up" the Vengeance considerably, possibly using secret technology developed personally for him. So while it might not be as powerful as 24th century starships..... it might be less self-sustainable than the Enterprise D or E which were designed to be ships with a long term space mission..... it can achieve many things that neither of those starships can. Especially in a battle scenario.