I have had my last lathe for over fifteen years. It is a 15" Craftsman which was also marketed at one time by Palmgren. In my shop this machine has been beaten and abused for some time and works well for me. Some others have had difficulty with this lathe but I have no complaints except for the manual. It has an introduction to turning that is only exceeded in poverty of description by the lack of maintenance directions and poor parts descriptions.
As is indicated by its name, this lathe will swing a full 15" diameter piece over the lathe bed and 11 1/2" over the banjo while spindles can be up to 38" long. It also has a rotating head and can easily turn an 18" bowl and likely larger. Speed is variable with a Reeves drive mechanism, an old and established mechanical speed changer which uses variable width pulleys to affect the alterations. I have turned a 13" diameter, 29" high, maple mushroom on this lathe with no difficulty. It weighs about 180 pounds and its bench is anchored to the floor. Speed ranges from 400 to 2000 rpm.
All these lathes "work" that is to say they turn wood round and will let you remove some of that wood with sharp tools. It is up to you to determine which size of lathe will best suit your needs. Keep in mind an old adage, "A large lathe will turn small pieces but a small lathe can not turn large ones." I would advise setting a budget and getting as much lathe as you can afford and still fits in your shop with enough room to safely and comfortably maneuver. Remember that a lathe is merely the start of the budget. Unlike your table saw that likely arrived with a blade installed or ready, a lathe is merely a lathe. It spins wood round but probably did not arrive with any tools to cut that wood. Tools, sharpening station, and other accessories are needed.