Joe, The box (finger) joints are about as strong as you can get and probably not necessary. I used them on the boxes form my mono-blocks because I wanted the vintage look and there was little glued surface area - they need to be strong as each amp weighted about 40 lbs. You can make box joints with a table saw. I used a router dovetail jig because I wanted them perfect and my table saw tests were not. If you're not looking for a museum piece the table saw will be fine.
When I built my sub enclosures I used 45 degree offset cuts made with a 3/8" straight router bit. This was in 3/4" MDF. This type of joint is very strong and even more so if you use internal braces (I did). See below:
Don
