You doubt, but i owned all of them and SP-20 is much better than SL1200mkII if you will make a nice plinth for it, my friend replaced his rewired SL1200mkII with SP-20 + Lustre GST-801 and the difference is huge!
The SP-10mkII is the ultimate for extremely low price, i paid no more than $1200 including shipping for my unit 5 years ago (it was in mint condition), now they are a bit more expensive (maybe $1400), but anyway it’s simply amazing turntable.
However, i prefer my Luxman PD-444 to all of them.
I can not speak about the Lenco, never owned, but i love Direct Drive turntables, personally i don’t want any idler drive or belt drive in my life.
I have tweaked my pair of SL1200mkII long time before i bought at SP-10mkII. In my opinion the cartridge is more important, my first top class MM were Technics EPC-100c mk3, 205c mk4. On stock tonearm they are great if you can find them with strong damper (which is very hard to find). I even tried ZYX Airy III on stock Technics tonearm with KAB fluid damper. But i was more impressed by the EPA-100 tonearm on my SP-10MKII with those cartridges and later Reed 3P "12.
My advice is to start with full re-wiring and MM cartridge for your stock tonearm, the AT-ML170 is a killer cartridge for this arm even without fluid damper. It’s a mid compliance cartridge, so you don’t need super light or very high tonearm for it (which means that you can swap the arm later). My favorite is AT-ML180 which i use myself. I don't think you will buy a super expensive tonearm for your SL1200mkII, because if you do it's a bit crazy and not worth it (for this particular turntable). Luxman TA-1 with removable armwand would be nice if you gonna use some high compliance cartridges like Stanton or Grace or Sonus, i believe this arm is rare with its heavy stabilizer, but still under $750. Actually Grace F-9F or F-14 are quite good even on stock technics arm with fluid KAB damper.
The SP-10mkII is the ultimate for extremely low price, i paid no more than $1200 including shipping for my unit 5 years ago (it was in mint condition), now they are a bit more expensive (maybe $1400), but anyway it’s simply amazing turntable.
However, i prefer my Luxman PD-444 to all of them.
I can not speak about the Lenco, never owned, but i love Direct Drive turntables, personally i don’t want any idler drive or belt drive in my life.
I have tweaked my pair of SL1200mkII long time before i bought at SP-10mkII. In my opinion the cartridge is more important, my first top class MM were Technics EPC-100c mk3, 205c mk4. On stock tonearm they are great if you can find them with strong damper (which is very hard to find). I even tried ZYX Airy III on stock Technics tonearm with KAB fluid damper. But i was more impressed by the EPA-100 tonearm on my SP-10MKII with those cartridges and later Reed 3P "12.
My advice is to start with full re-wiring and MM cartridge for your stock tonearm, the AT-ML170 is a killer cartridge for this arm even without fluid damper. It’s a mid compliance cartridge, so you don’t need super light or very high tonearm for it (which means that you can swap the arm later). My favorite is AT-ML180 which i use myself. I don't think you will buy a super expensive tonearm for your SL1200mkII, because if you do it's a bit crazy and not worth it (for this particular turntable). Luxman TA-1 with removable armwand would be nice if you gonna use some high compliance cartridges like Stanton or Grace or Sonus, i believe this arm is rare with its heavy stabilizer, but still under $750. Actually Grace F-9F or F-14 are quite good even on stock technics arm with fluid KAB damper.