I was running some rudimentary probing thru LNbig a couple weeks back, no hard numbers but inbound shortage is v apparent. You can see this in the difficulty it can take in trying to rebalance lnbig channels

Yes I'd classify LN+ seperately, no actual buying/selling occurs there atm. Swaps are essentially "I'll open a channel to Bob if Alice opens a channel to me" -- it is not a very selective process and the 'quality' of peers highly varies, you basically open a chan to random peer and receive a random chan in return. Some swap peers are great, some are bad. Contrast that to Magma where you may be selective in your peer or to Pool which uses an internal scoring system