It sounds like you already made your decision, but I thought I'd throw my two cents in as well. I recently got into this wonderful hobby for myself and wanted a full DCC system. I'm in the process of putting together a basic 4' x 8' layout with a couple sidings, but what I was really interested in was computer control and automation. Given that I'm new to the physical process but I have a background in computer science, I went looking at the digital systems available with this kind of eye.
My local train shop (a great place I used to visit with my dad years ago when I was a kid and he ran O scale trains at Christmas time) really pushed the NCE systems because they've had great experience with them and the company is based in New York and they can get great, fast service when needed.
This system seems nice if you're an "old time" model railroader, as it is setup with the electronics in mind. It's good if you're used to dealing with voltage levels and the like. However, if you're a "computer geek" as they call it, the Digitrax system is made from a computer user perspective and you'll probably have an easier time with it, although both systems are easy to setup and use. Where I was sold on Digitrax was when it came to my needs for automation, namely with regards to block detection and network interfacing.
First of all, the way Digitrax does block detection I think is better than the way that NCE does block detection. NCE does it using an auxiliary unit and individual detectors that run in between this unit and the track. The Digitrax method is a single unit that simply wires to your track directly and supports up to 16 detection sections on a single unit.
Secondly, as a "computer geek", I really like Digitrax's network architecture. Like bob said in an earlier post, their "LocoNet" network is basically a computer LAN. It uses industry standard RJ12 data cables (similar to phone cables, which are related to computer LAN or "Ethernet" cables) which you can get from pretty much any cable supplier. Most other DCC systems (including NCE) use a simple polled bus architecture that is inherently more limited. When I take my stationary decoder I'm using to control my turnouts, my block detector and my command station together, I simply connect them using these data cables and they are all networked.
What this means is that, once connected to a computer through my LocoBuffer USB adapter, the computer can see
everything going on in the network very easily. That means every loco command sent, every turnout command to change positions, every notice that a block is occupied or not, etc. is all put on the network for any connected component to see. This is pretty much a necessity for computer automation to take place. It also makes the Digitrax system very easy to expand and add new components down the road. Simply connect the new component to the network with a data cable.
Now this is not to say that the NCE system is bad, far from it. If you're not doing computer automation like I am, this doesn't really matter much to you. However, for my purposes, the Digitrax network and overall expandability of the system really sold me, and I think it's a very good quality in general. I picked up a Zephyr starter set and I've been loving it so far. I'll post some pictures once I get my block detector unit hooked up and working.
Hi and welcome 
, it's still nrma dcc!! So you can use just about any compliant device w/ it. I have a couple of lenz dcc stationary decoders and they work great!! So far i only have digitrax mobile decoders but once i get into sound i think the tsunamis have what i like. 
) but this is mainly due to the fact that TrainController is only for Windows. However, the LocoBuffer USB does in fact come with drivers for Mac OS9 and OSX, as well as Linux and Windows. If you're using JMRI, you should have no problem as this is cross-platform thanks to Java. Mind you, I've never used the LocoBuffer USB with anything other than a Windows machine, but given that it comes with drivers for other OS's, you should be fine.