For me it's like choosing your favorite child/sibling/relative, a question that can't really be answered. So many pros/cons, not the mention pros/cons of the underlying resorts themselves.
But if I have pick favorites, for an adults only trip I lean:
- Any of the Epcot resorts given the location/walkability to Epcot. I don't personally enjoy BWI/BWI CL (mainly due to the rooms/theme) but I'm in the minority as it has a pretty hard core following with perhaps a bit more of an adult feel than other resorts and CLs (although of course kids are everywhere at WDW). It consistently gets strong reviews for CL food and service, probably the best of the bunch. YC CL tends to get the nod from us - nice, sleek rooms, the resort and CL has a slightly adult and/or quiet feel to it, decent food/beverage offerings. BC CL is basically identical from a CL perspective, but I prefer YC over BC - BC is a bigger resort, can tend to have more families, noisy lobby, etc, so BC wouldn't be on our list.
- If location/walkability isn't a factor, I'd give a strong vote to GDT CL. Beautiful lounge, great CMs, and they really do a good job with the quality and quantity of offerings. Nice room options to guarantee a king bed if that's desirable.
- If you're more of a MK couple, then CR Tower Club/14th floor or GF Main Building would get serious consideration from us.
When comparing all of the variables, for us if we're thinking about an adults only trip CR Tower Club and YC CL tend to get the call... followed by GDT CL if it's a bit longer trip and we're not pressed for time/don't mind not being able to walk anywhere.
If applying cost to the equation....GDT CL is the best $ value....MK CL prices are more splurgy/annoyingly high....Epcot CL prices are still high but typically a little less stratospheric than the MK CLs.
Have fun!