To be clear, the bit about "most accurate pollster" is Stonehaven's own self-description, but I always put that in because it upsets our resident unionist troll KC.
It was Stonehaven who, a few months ago, first started the trend of MRP polls showing an SNP overall majority, and I must admit I was surprised that YouGov of all companies ended up following their example. Remember, however, that Stonehaven have stated that they factor tactical voting into their headline projections, and once again they've found that the SNP benefit more from tactical voting than any other party. That seems intuitively implausible, so if there's any health warning to be put on these numbers, that would be it.
Seats projection (Stonehaven MRP):