I have the Pfaff P3 - similar to the Tin Lizzie 18 - works well, and while we always want "more" - I find I can do pretty much anything I need to on the 18" throat space.
The machine is not finicky at all, and I don't have tension issues unless it's "operator error".
But, happy as I am with my machine, I second the opinions given about test driving to see what works for you.

Like ckcowl & cari-in-oly I have the HQ Avante. Ha the HQ simply 16 before, sold it on Craig's list and did a 3 way trade to get the Avante. I love it!