Yes, a dovetailed joint is stronger, but at that point you are WAY past the point of dimishing returns. It isn't really worth it, and all that would change in the box is the amount of effort you have into it.
No, it isn't worth it for box building. Specialty joints aren't really worth the time, but for speaker building, then yes, it's a good idea. If you want a better bond, a miter joint would work while not being too ridiculous.
There really isn't TOO much difference. My only deciding criteria is the ease of use for each glue. My personal favorites are Titebond II (buy it by the jug) and Elmer's ProBond. T3 is technically stronger, but it takes a decade to dry, and you won't notice the difference unless you're trying to make your enclosure explode. T1 is a good glue for smaller applications. It tends to flake easier, but dries extremely fast. I use T1 on sealed and small ported enclosures where the working time doesn't need to be very high in the first place. ProBond is just about the same as T2, but it sands SOO much easier. Whereas T2 just kinda peels away, probond literally sands off in a powder. I use it on speakers mainly, because it's harder to find around here. T2 is your overall best bet.
A miter joint is done by cutting the edges of the panels at 45 degree angles. That way, you have over 1/5 more surface area (think 45-45-90 triangle) to glue. There also isn't a way for the internal pressure to blow one of the joints apart easily because if you don't set the joint properly, it won't look right. It's an easy way to get more strength, I use it only exclusively in home audio subs though.
I always use miter joints on boxes I am going to paint. Not because they are stronger but because it makes finishing the box a LOT easier. Miters are easy if you take your time and think about what you are doing.
I use to cut the miters when finishing up tiling on roofs, takes some getting use to, but they can look oh so sexy when done right, never even thought about that with my box though //content.invisioncic.com/y282845/emoticons/blackeye.gif.66a1670f5aaf7f406e783a63e3387dc5.gif
