When I first got my Tin Lizzie I hated it...too much of a learning curve. That was in April and now I love her to pieces. The main problem I had was the tension. With some help from my DH, we figured it out and as long as you do the 3 step maintenance before starting, everything should be smooth. 1: Clean machine and rails good. 2: Oil her if necessary. 3: Do the bobbin test - kinda like using a yoyo in the palm of your hand.
If you get a different machine, will you have the same issues? Did you test drive either machine, prior to purchasing the Tin Lizzie?
The rep I bought mine from made lots of promises and has yet to follow through with me buying the TL from her, so I have figured everything out on my own so far, along with the help of youtube. I wish you luck with whatever you decide, but, since you didn't state what problems you were having spefically, I would give the TL a second chance JMHO.