I have the Visionline.
What makes in notable and the price difference.
#1 3 speaker system. 1 inside the engine, 2 inside the tender. This alone is a HUGE difference.
"Dual Sounds
Your VISION GS is equipped with dual sound systems. The locomotive features a single speaker in the boiler, and the tender boasts two speakers, give extra bass. The sound systems work in unison to make this engine roar to life!
Many of the sounds will be concentrated to one of the two sound systems, giving a more appropri- ate location of where that sound comes from. For example, the bell, chuff, whistle, and cylinder steam sounds primarily come from the locomotive, with reverberated sounds playing in the tender. On the flip side, the sounds of fuel and water loading, and CrewTalk dialog come from the tender.
Another new feature exists with the tender. If the tender goes over a dirty spot on the track and momentarily loses power, the sound system in the tender will restart automatically and pick back up where it left off, like it never even happened! Never again will you have to reset the engine, or try to add in a tedious battery backup."
#2 Reciprocating cylinder steam is a big deal. This is the parlor trick of this engine.
#3 Force coupler- this is another cool feature. It does sense load and increase the labor chuff dynamically. Another huge and worthwhile feature.
Again, just on hardware /electronc features alone:
3 smoke features in the Visionline (Main, reciprocating cylinder, and dynamo) VS, only 2 in Legacy (main, whistle steam)
3 speaker system with 2 sounds cards, one in the engine and 2 speakers and separate sound card in tender VS 2 in tender only on Legacy version
Legacy version is pre-Bluetooth (not saying bluetooth is a showstopper or must have) where the Visionline is with Bluetooth control
Only the Visionline has force coupler sensing that dynamically changes the chuffing based on actual real tractive force.
Forgot another major feature of the Visionline- 5 different Whistles and City horns.