Raglan Road is one of our favourite spots in all of Disney to not only eat, but just hang out and have a few drinks as well. We have eaten at both places recently (in the past week) and Raglan Road is still one of our favourites.
The Boathouse is a nice place to eat. The atmosphere is cool & different (to me) for Disney. The out door bar area is a really cool place to hang out even when it's hot out here in Orlando. There always seems to be a decent breeze moving off the lake.
The Boathouse is a little more pricey than Raglan Road of course. Though the differences in the menu items make both places an enjoyable meal. I can break down our last two visits to each on prices and quality of food. Both at dinner time.
Raglan Road
Starter: Dalkey Duo - $12.00
Main Course: Curry Chicken Pie - $19.00
Main Course: Shepherd's Pie - $19.00
Drinks: Well, how about just the food cost

sorry
Total: Around $55.00 or so with tax
The Boathouse
Starter: Crab Claws - $19.00
(Shared) Main Course: Beach & Sea Lobster Bake - $60.00 [this does feed two people easily]
Total: Around $85.00
You can see that The Boathouse was around $30.00 higher, though you can chalk that up to the meal choices as lobster is a much more expensive dish than what's in pies at Raglan Road.
Overall, both places we enjoyed very much. Both the food and of course the atmosphere. Raglan Road obviously more of a pub atmosphere with louder music, other guests, etc. The Boathouse has a nice atmosphere for the themeing of the restaurant and we were able to have a more personal (for lack of a better term) conversation with each other and other couples than you will inside at Raglan Road (to me).
I do not believe you would not enjoy either restaurant. Though it is more what you are in the mood for or what you feel "up to" as far as atmosphere when you make your selection.
Being born & raised in Florida, seafood to me is something of taste and what I am in the mood for. If I really wanted great seafood, I would go to a beach community near by and have a better meal for less money than at The Boathouse. Having said that ... The food here was not bad at all. To me it is just a bit pricey (even for Disney) when it comes to seafood.