I've also been a long time Miata owner that recently switched to a Boxster. So far I've owned 3 of them and still have 2, one of which is rather forlorn Spec Miata SCCA race car that has been a source of parts to keep the daily driver going
Moving from a Miata to a Boxster is kind of like switching from Rye Whisky to Single Malt it's more refined and smother in so many ways. Both are quite enjoyable in their own way.