Probably isn't a consensus here, because what we do with them is so wide ranging.
I've had cancer twice in the last four years, so I don't collect anything
I've had a featherweight for many years that I never did cotton to and should shift.
I have a 1948-9 era blackside White Rotary, love it, thumpa thumpa as I go. Gift from a client.
I have a 1960 Singer 404, love it and it is very light so a good class machine. Craigslist
I have a 1950 japan made BelAire which the folks here helped me to turn into a hand crank to take when Rob is fishing. En plein aire stitching is lovely Goodwill auctions
I have a Janome 8900, a gem of a machine but I wish I'd thought it through before I bought it, I only do patchwork now, so all the extra stuff was wasted money.
I can see the lure of vintage machines, they are so cheap and beautiful.
edited to add: (maybe I'm a collector in spite of myself...)
I have a White treadle in a twiggy cabinet as an entry tabl, $75.00 bought specifically for the entry.
and I have a Blackside Singer 66 in a treadle that I use. Gift from Dick Wrightman/Treadleon
Everything but the Featherweight and the entry machine is out, and set up for use.