I had a Brother cheapie and it had tension and thread problems also.
My old Singer was a workhorse but just did not do all I needed for quilting.
I bought a Husqvarna Viking at Joanns. It is computerized and I leave it on all day when I am quilting. So far it works just fine and I like all the special quilting features. It also has a 10inch throat which is very helpful.
It is handy to take in if I ever need repairs, just take it to Joanns.
Its to new right now to let you know of problems but I sure will hollar if I do have any.