Assets from older versions of Trainz may have errors that did not stop the asset from working in those older Trainz versions, but are taken seriously by newer versions of Trainz (e. g., TS2010) and cause an asset to be considered "faulty". In TS2010's regular mode (known as "Native" mode), these faulty assets can not be used in Trainz; they will be listed in red in the tab they are listed in in Surveyor.
Compatibility mode allows these faulty assets to be used, at the cost of possible reduced performance in Trainz, while still allowing TS2010 features like SpeedTrees and of course more detailed modern Trainz content to be used.
Compatibility mode also allows assets with blended alphas to be displayed very close to how they appear in older versions of Trainz. TS2010 displays blended alphas differently in Native mode, ruining many billboard trees, etc., so switching to Compatibility mode will cause these ruined assets using blended alphas to display correctly.
It is often possible to repair the errors in faulty content so that those assets can be used in Native mode. There is a project going on called the DLS Cleanup where members can fix the errors in fauty assets from the Download Station and upload these fixed versions with a higher KUID2 version number, causing Content Manager to pick these up as updates, allowing people to download these updates to obtain fixed versions of faulty DLS assets they have.
SpeedTree is a 3D foliage technology. SpeedTrees are 3D trees rendered by your graphics card, not your processor like old billboard trees. Asd 3D trees, they are much more detailed than old billboard trees. Some people around here like them, some hate them; I am in the "like them" category. To me they are far superior to billboard trees. No more billboard trees for me, instead I'm going with speedtree. SpeedTrees can be seasonal assets, meaning that a tree may have green leaves in the summer, fall leaves in the fall, and no leaves in winter.
Do not listen to the anti-SpeedTree comments in the forums; judge them yourself with your own eyes, after you have downloaded the excellent 3rd-party SpeedTrees by McGuireL and Pofig.
Content Manager (CM) is a newer version of the old Content Manager Plus (CMP) in TRS2006. I find Content Manager easy to use.
TS2010 does have some interface changes, such as the integration of the Driver and Surveyor route/session selection screens into one "Routes" screen. I of couse would not know how quickly or well you would adapt to TS2010, but remember that there are people here on the forums willing to help you, and you have the forum's Search function to look for threads that were created in the past.
I moved on to TS2010 from TRS2004 going on 2 months ago and have not gone back.
Have a look at Dermmy's superb Kanshino Narrow Gauge Railway route for TS2010 at
http://forums.auran.com/trainz/showthread.php?t=74045 to see an example of the realism that TS2010 can accomplish.
If you run and old route using old content in TS2010, then it might look similar to how it was in TRS2004. However, if you run a route that uses newer, detailed content, then you will likely notice a difference.
Regards,
Retro.
