Most important to me is Trainz is fun. There are several prime reasons for this, and a few additional reasons. Trainz is fun because it lets me take control of more than one locomotive at a time; MSTS lets me control only one locomotive at a time. Trainz is also fun because the couplers work properly every time I try to uncouple or couple cars. This is important to me because I like shunting cars. Couplers in MSTS sometimes work and sometimes don't work.

Another thing that makes Trainz fun to operate are the turntables that actually work. With Trainz you can operate an end-to-end layout with steam locomotives and still be able to turn them around at the end of the line and run them the other way. (I realize that on some prototype operations the steam locos just operated backwards, but I do like having the option.)

Some additional things that make Trainz fun to operate are the ease with which I can tell what the situation is and what I'm doing, and the ease with which I can perform certain operations. For example, all I have to do is hit the M key to display a map of where I am. I can zoom in or out and see the track plan, switches, and direction of switches. Hit the M key again and the display returns to its previous state. (I don't know how to do anything like this in MSTS.)

Another nice touch is the visual display of switch directions afforded by just placing the cursor over the switch. A green and a red arrow appear. The green points to the direction of the switch. Click either arrow and the setting (and arrows) reverse. (In MSTS I have to use different keystrokes to throw the switch ahead or behind. Just try to remember which way the switch is set to begin with, or which switch is before and which is behind if you are using a diesel switcher.)

Similarly, I like the Trainz method of letting me hit the D key to indicate my intention to uncouple something and then click the area where the couplers are to accomplish the uncoupling. It took me awhile to realize I then had to set the handbrake of the unpowered cars by selecting one of them and hitting the X key, but that's not hard to do. (With MSTS, uncoupling is more abstract and may or may not work.)

There are some intangible items as well: the visuals and the sounds. Trainz is capable of spectacular, highly detailed scenery. The fact that many layouts do not exhibit this has two parts to the explanation. The easy part is the designer didn't make it that way. There are reasons for this, which I will go into later. The other intangible is sound. Trainz has great sounds for rolling cars. Trainz also has great sounds for thunder storms; and the storms themselves have great visual effects. I sometimes want to run for cover to stay dry; and I sometimes think I can smell the wet grass.

Then there is the ease with which you can build layouts. Some argue that this has led to a lot of mediocre layouts -- and perhaps this is so -- but more importantly it adds to the fun you can have with Trainz, and that's why I like Trainz.

Trainz is not perfect, so I need to be honest about what the drawbacks are. First, Trainz makes greater demands on my computer's speed and volatile memory. MSTS, on the other hand, requires greater disk space. I'm not finished with this point. It's imprtant, and I'll come back to it.

Second, Trainz has provided a scripting language for creating scenarios (called activities by MSTS). The documentation is appropriate for a programmer, but not the rest of us. My impression is that Auran simply didn't get around to completing the kind of scenario building wizard it would like to have, but someday will do so. Meanwhile, we are all awaiting the release of Junction Master (see my link to TAC), which should make the task a breeze.

Now we can talk about system resources. The great scenery potential and the ability to run multiple trains place greater processing demands on your PC. Groups like TrainzProRoutes have shown that spectaular, highly detailed scenery is possible with Trainz. But those of us with low-spec PCs have found that certain highly detailed routes will not not run smoothly, thus we appreciate the layout designers who leave the added detail to us to place as we see fit.

We have also found that it is sometimes necessary to turn on the distant fog setting to obscure the reduced draw distance setting we have chosen (to conserve resources), and to hide the layout baseboard edge that sometimes is visible. This latter problem arises when the designer thoughtfully limits the layout width to keep resource requirements under control and when we elevate our camera position to extreme heights (not possible with MSTS) that naturally display the designer's little secrets.

On the whole, none of these drawbacks is a showstopper for me and I am having great fun operating Trainz. I may even upgrade my PC one of these days.