Danno, we use both a water based tempering machine and the large matfer trempreuse a air tempering machine, the water controlled machine is not matfer, but a local brand called Roband that uses a water jacket and thermostat, both are very good and will take 15 - 20kg of chocolate. Go for the largest you can afford in capacity as you will be suprised how much chocolate you will need once you temper it. My understanding of some of the smaller units are that the container for the chocolate is a sealed unit and cannot be removed, this can be a pain in the arse, the matfer and Roband/or similar have removable basins which means you can quickly switch over your chocolates.
Look at the matfer also because of the wheel and motor attachment, an excellent add on!
If it is any indication, I recently snapped up 2 matfer machines at auctions over here, they are so good I could not pass them up, the beauty of Matfer are that they are so well made that they will outlast you!, the problem is sourcing parts if you break them, I have an early model of their sugar lamp and it required a new dimmer, could only get it from France and it took 3 months, the upside, it was free! They will give support for the life of the equipment, thats how highly they recommend their own equipment!!
I hope this helps,
Regards,
Felixe.