The "T" in 4250TN stands for Tray, as in 1 x extra paper tray and the front cover pulls down to allow paper to feed from the front, so you have the opportunity to have three different types off paper loaded and ready to print.
The "N" stands for Network so you will be able to connect lots of computers to this printer.
I have seen this printer connected to about 9 computers and handle it very well, however ultimately it's down to the volume of printing you're expecting it to handle.
This machine has a small footprint so if space is at a premium in your office but the workload is high, this might be the printer for you. Hewlett Packard make good reliable printers in general and if the LJ4250TN develops any faults H.P. parts are cheaper and more easily available than most.
There is one fault I am aware of with this machine relating to the duplex unit, if you expect to add a duplex later and do a lot of double sided printing, it has a habit of becoming a bit noisy; there is a cog that wears under the extra load caused by the duplex. However this is very minor and can be fixed easily.
The HP laserjet 4250TN is retailing for around £900.00 at the moment and IV seen them as low as £600.00.
Remember if you're buying second hand, or a reconditioned unit, make sure you get a configuration and consumables status page printed off the machine. These will tell you the amount of pages the unit has printed, error messages, life expectancy of the consumable parts and the level of Toner remaining.
Toner for this printer is about £90.00 so you don't want to be forking out for toner as soon as you've got it.
This is a good solid printer and I would recommend to anyone.