Contemplating a Lancair to downsize my six seater to a four seat.

Seems, though, that the Cirrus SR-22 is rather more popular than the
Columbia 350.

Can anyone shed some insights on these two side-by-side?

Having flown both the SR22 and 350 quite a bit, the answer is clear:
Lancair Columbia 350 or 400. Go fly both and see for yourself. It's kind
of like the old Beta vs VHS or Mac vs PC issue. The better product isn't
always the most popular one.