These engines are as detailed as you will find in many of the brass models. Models also have great slow speed control.
The only warning on these are the steam engines. Beware the first releases as they have no traction tires and are unable to be upgraded. Also check to see if the tender has electrical pickup or not.
Without traction engines the early releases can hardly pull a load up a 2% grade without slipping. Without the tender pickups the engines often stall at switches.
The recent steam engines releases are acceptable. check to make sure the engine has the traction tire and the tender the electrical pickups.
Check around for pricing, the engines are quite expensive and many vendors offer substantial discounts.