Most of the 5000s which are extant are the RX-5000. The "RX-" designation is a solid bearing. There exist some SX-5000s as well. The "SX-" prefix denotes an air bearing turntable. The SX-8000 and the SX-8000 II are roughly similar, but the SX-8000 II is physically more 'integrated', and it usually comes with a vacuum hold-down platter. The SX-8000 tends to go for less than the SX-8000 II but I have not seen an SX-8000 II for sale for many moons (last one I saw went for something like $15-16k if I remember correctly). The SX-8000s I have seen recently (last 18mos or so) have gone for $9-15k on Japanese internet auctions, in varying condition. There seem to be a fair number more of them out. I have never seen an SZ-1 for sale, though I imagine if it came out, it would be more than the SX-8000 II.
I have an SX-8000. I have compared it to the best Japanese DDs of the era but not to rim drive tables. I have not heard a table before or since which digs as much info out of the groove as the SX-8000 with a MAX-237 arm (don't have a 282) and a ZYX UNIverse. When perfectly dialed in, it is a very smoooooooth sound. The large DDs (Exclusive P3, Technics SP-10Mk2 & Mk3, and Sony PS-X9) are also quite good, and you 'feel' the drive which you don't get with the Micro, but the Micro is soooo quiet.