I can agree with much of what is said here. It all boils down to what makes you happy. Trainz versions are cool this way, unlike many other applications which will lock you out once you change versions where it's all or nothing once a new version of something comes out.
Keep in mind that once you create a route in a newer version, you cannot bring it back to a lower one due to file structures being changed. The newer versions of TS2010 and up have layers which were non-existent in previous versions, and then again layers have changed again in TS12 SP1 and up. This issue, not just the layers, is not uncommon with many applications where they can read in and use older files but not the other way around.
Since T:ANE HF2 has come out, I've gained more confidence with the product and I've since migrated most of the routes over I wish to keep from TS12. Initially I migrated about 165,000 assets from TS12 with 7,500 needing repairs. Out of this large number, 2,500 were useless due to being faulty due to mesh problems, and other things that I could not repair. The remaining 5,000 errors were simple texture, typos, and the other usual stuff. My content is now error free, according to T:ANE, however, I do have a few missing assets in each of all of the routes, except for the most recent ones, due to using older built-ins I didn't import, or payware items that have not been updated yet. These assets are not show stoppers as they are buildings and such which can be replaced as needed. With the improvements I have seen in the SP1 beta versions, I am even more confident that the program will truly be a replacement for TS12 when the time comes since the program's stability has increased tremendously since the beginnings.
I'm not saying that I don't still use TS12, which is now the old stalwart of Trainz and is fairly stable, however, when I do use it I can see all the shortcomings of it such as the shorter draw distances, though I don't set my draw distance out to 15km in T:ANE either. In T:ANE the biggest difference is are the shadows, lighting, and no pop-up assets, which really did ruin any routes, especially those with far off vistas or open areas with distant scenery as that would be lopped off.
Here's some screen shots of a recent import - my Cape Ann Transit route, which is based on a DEM of the Cape Ann region in Massachusetts. In the left two pics, the distant shores are non-existent in TS12 or keep popping in and out and redrawing slowly. Both of these scenes are far from complete and need various details added. The textures too need replacing as they are too bright, or just aren't right. These are little things which are more apparent due to the lighting differences, but are easily replaceable and doable repairs, so to speak. The scene on the right shows some of the shadowing, though not the best scene on the route. Overall I am quite pleased with the import results.


