Yeah the end with Empress Hoshi Sato is a great line but it took a while to get there. I mainly enjoy it for looking at the ship. And seeing the green wrap around shirt again!
I liked it for those reasons, plus the Mirror Dub inside of me just found it delicious to watch these familiar characters with different (in most cases evil) personalities.
I thought it was great fun.
But to be honest, I was expecting the writers to bring one of the MU characters into the "normal" universe at some point -- the opposite of how the MU was introduced in TOS and DS9. DS9 did that in later episodes, but this would have been a unique way to introduce the MU on ENT. Imagine if Admiral Forrest found his way to the normal universe for several episodes, then plotted some evil plan and really screwed things up.
The other thing to remember is ENT was ended prematurely. Who knows where they would have gone with it if they had 3 more seasons.