I have a Viking Branded Tin Lizzie. It's identical to the Tin Lizzie 18 LS. I really do like this machine. It is very unfussy about thread cotton, cotton poly, metallic all no problems at all. The tension is very easy to set and maintain. I have an inspira frame which I'm less thrilled with. I find it a bit stiff. I can do SITD pretty much without a ruler because the trolly really wants to go N-S or E-W. Large curves and feathers are actually not too bad to do, but I have not been successful with smaller, more detailed quilting like pebbles or micro stippling. I get square pebbles and jagged small stipples because of the stiffness of the frame. Some of it I'm sure is due to lack of practice on my part, but I've been successful on a high end set up at my friend's. Her frame was 3 times the cost of mine, so in some cases, you get what you pay for.
I know that some frame manufacturers offer upgrades to their trolly wheels, but there are none that I'm aware of for the inspira.
If you are not familiar with the working and maintenance of a mechanical sewing machine, you need to have a good dealer that you can rely on. There have been many negative posts on support directly from TL. I can't comment on this because I've never needed to contact them directly, I've either done my own trouble shooting (you mean you really have to follow the threading instructions in the manual?) or my dealer helped over the phone.
I got the set up used from my dealer for a great price and all in all I have been very pleased. I don't do quilting for hire, just for myself, friends and family.