Bias alert - we're owners at BLT. I'll do the cons first, because I don't think there are many!
Cons: 1) It's not super-Disneyish. It feels like a stylish hotel. Except for the staff and the subtle Disney artwork in the rooms, it could be any hotel. That's actually a pro for us, but I know lots of people love the Disney theming to be a little more intense. We like coming back to a resort and room that isn't screaming MAGICAL at you after a full day in the parks. 2) There's no onsite restaurant (except for the Top of the World Lounge, which has limited hours and admittance). If you want a quick meal you have to hoof it over to Contemporary. Particularly if you have a deluxe studio. 3) The pool is small compared to the other deluxe/DVC resorts. But then, it is rarely crowded either. And you can walk over to the Contemporary pool (five minute walk max...).
Pros: 1) Walk to Magic Kingdom. 600 steps they say. All I know is those 600 steps seem pretty sweet as I walk past the sea of tired and cranky humanity waiting for the Pop Century bus at closing time! I've been in that line, many times. It ain't pretty. 2) It's compact. Very quick walk to the pool and the pool bar from almost any room. We stayed at AKL Kidani Village on our last trip. Amazing experience and I would recommend it to anyone, but be ready for the daily workout going back and forth to the pool or the lobby! 3) It's attached to the Contemporary. Take that foot bridge from the third floor and you are right in the middle of the coolest hotel lobby on property. And a few short steps from the monorail station. 4) Room are great, the deluxe studios have a slightly different layout that we like. The two-bedroom suites have three bathrooms while most other properties have two bathrooms. We like that. Lots.
It used to feel much more like a typical condo building until they added the check-in desk. Now there are always plenty of staff around to answer questions and you can check-in onsite instead of over at the Contemporary. There's a concierge too.
There's a small beach area, and you access to the larger ones at Contemporary. The BBQ area is very close by as well, and nicely secluded. They also have a community room like the other DVC resorts with games and DVDs to borrow.
For a couple with no kids, I'd say BLT is a no brainer. Unless you really want the immersive Disney experience, then look elsewhere.
Either way, have a blast!