cost - BWCA would cost you $15 per person per trip (I think that's the going rate)so $30 for you and your Bro. Algonquin would cost you somewehre between 15 an 20 dollars per person per night - so that's about $30 x10 = $300 or so. No fees that I'm aware of in Adirondacks.
Passports - got to have em to get back into US - and just f.y.i., any DUI on iether o fyour records can result in not being allowed to enter Canada.
No matter where you go, if you can arrange to enter on a mid-week day instead of a weekend day, you will see fewer people - you won't be "in sync" with the majority going in/coming out on Sat or Sun.
Black Fly season - if you've never experienced hundreds of black flies getting in your eyes, in your ears, stuck in your hair, in your mouth when you try to take a bite of food - - well, don't miss your chance, and be sure to go in June -- otherwise, to avoid Black Fly season, go later in the year, though the first week of June is usually still mellow as the bugs are jest beginning to hatch then - but weather patterns make a diff.
Gear? you said experienced campers ? if that meant experienced backpackers, your good to go - if not, you might consider an outfitted trip.
Canoe - got your own or rent ? if you have a 90lb Disco, forget about portaging it and rent a kevlar ultralight. (its possible to do a BWCA trip with minmalnumber portages if you go out of Moose Lake
Fishing ? BWCA is Bass, Walleye, adn Northern Pike and Lake Trout
Algonquin and Adirondacks are gonna be just trout, mainly Brookies
Based on my personal preferences and experience, I'd suggest the BWCA for your trip - everybody ought to go there at least once, and you can always go to other areas forfuture trips.