Spin Clean as good as RCM, ie-VPI etc?

Yes they are and do.

I have a VPI and bought (2) spin cleans. I use them together. I put the Spin Clean fluid in the first one, dry the record, put it in the second Spin Clean with Walker Audio active enzyme cleaner, dry it off, then rinse and vacuum each side of the record on the VPI with ultra pure water (gotten from a scientist friend!!). Works great.

Really old records I steam on the VPI first before I put then in the first Spin Clean.

To my knowledgde, there is no sustitute for a vacuum incorporated into the cleaning process whether it be a RCM or a DIY set-up.

I'll throw the Gem Dandy into the mix. I feel I've gotten better results from my Gem Dandy than I ever got from my Nitty Gritty, and the sound of running water is much more pleasant than a vacuum motor. I might try the Spin Clean, though I do wonder about it leaving dirt on the record.

For not too much more than SpinClean, you can get the KAB EV-1 record cleaner. You add your own canister vacuum, and you have a low-budget vacuum cleaning system that cleans as well as any entry level VPI or Nitty Gritty. It is fully manual - you apply the fluid, spread it, scrub the LP, and turn the LP while the vacuum does its thing. I've had mine for several years, and it is fantastic, even with garage-sale records, which I buy often. One of the biggest bargains in analog audio, IMHO.