I had a TBC250 a couple of years ago and never had any problems with it until the carb needed rebuilt. Most people don't like Tanaka because they use a "brain" string head. The trick to using a brain head is to remember that to advance string on high speed you have to first advance string at low speed, and vice versa. In other words just standing there reving it up won't advance line. It takes a little getting used to but once you get the hang of it it's second nature.
I've got a simular head on my Shindaiwa's. They call it an automatic head. Give it high RPM's and the line advances, with no donut marks in the grass. I know Tanaka makes a great edger, but I don't know about any of their other products.
I had a Tanaka walk behind edger and a trimmer. They were both great. We inherited them through some transactions, so they weren't my purchase. I could tell you they were both great machines, but when they started to age a little, I couldn't get any parts for them around my area.