Personally, I think this had to be one of the better Voyager episodes. A worthwhile storyline, plenty of Humour, and enough action to satisfy.
In addition to the above, it was nice to see an episode that wasn't directly based on Voyager too. Unlike your typical Voyager episode, in Message in a Bottle, we got to see a little bit of 'home' and what was going on back in the Alpha Quadrant.
The episode focused around a new ship, and your typical Romulan plot. In addition, we also got to see other Federation starships (which was rare in Voyager). From a Nebula, to an Akira, to (two) Defiant's, along with some Romulan Warbirds.
All round, this was a great episode, and will remain one of my favourites for years to come.