We got a TT when DD was 5 months old and was really pleased with it. It is the best value item we bought really as it is still in use now, as a chair, and DD will be 10y in April.
We had the baby kit, but didn't use a harness (reins) as DD never tried to get out of it. We only used the harness til she was about 13/14 months, and then she used it more as a chair - but higher up. No problems whatsoever.
We have used it since with visiting children without the baby set but with reins as a harness and it has been fine.
Our TT is still in fantastic condition. It is very easy to use, really easy to clean and it looks good too - which was important to us then as we lived in an open plan apartment, so it needed to fit in with everythign else which was fairly modern looking.