I've got an SV08. It's not a perfect printer, but making a printer without the problems it has (e.g. the bed takes nearly an hour to settle after it's reached temperature, so it needs a long preheat for all but the shortest prints) would require making it much more expensive (e.g. a thick aluminium or graphite bed that wouldn't warp would add another 20% of the cost of the printer). That specific problem is sidestepped with the MK4S by simply having a much smaller build volume rather than because it's higher-end and more expensive. I've not needed support from Sovol (yet?), so can't comment on whether they're still super slow like they supposedly were right after the SV08 launched.