I agree with you “noname”. There is no real advantage using seconhand Tenor if the price is not half of original price.
In my opinion, if you are “newstarter” and this is your first Tenor unit, it is recommended to buy directly with Quintum and also pay for one year support.
They have very good and promp Tech support, with very resonable price. From Tech. support, you will get all info which you will required to start your unit and earn some money. In addition, all troubleshoooting could be done from QTAC. This is very important when you have running services/traffic. In most of the cases, you will get from QTAC all informations and you do no need to spend time in this forum, waiting for hints and replays, while you do not having any traffic.
For biginner is very risky to start without support, same as trying to do soem proffesional works/services, without any training.
If you have experience and already have one or two Tenors, with paid tech support, that is guarantee that you could look for some second hand units, where you could save some initial investments.