Two words for you, English J3 piper cub, "digital trims."

Any computer radio with digital trims is way more convenient than a standard radio with mechanical trims. I found myself spending the first two or three minutes of my flying time re-trimming my old Futaba 4YF transmitter because the mechanical trims would always get moved when carrying or storing the radio. My Futaba 7C with digital trims is always set perfectly when I take off because the digital trims on a computer radio don't get accidentally bumped or changed.

If you're going to buy a new transmitter, a computer radio with digital trims is well worth the extra cash. Even if you only have one plane and will only be flying a 3 or 4-channel trainer, digital trims are worth spending a little extra.