AR-VT-200 vs Vtl MB-450

Both are wonderful but i would go with VAC for best build and sound quality.

VTL service is first rate if you buy from an authorized dealer. If you are buying used in the open market you may encounter problems. 

The 450s are very friendly. That is they fail nicely simply blowing a fuse if a tube goes bad. Check the archives for stories of what ARC amps can do in the same situation. 

The 450s are also very adaptable to suit your speakers due to the adjustable damping factor

By the way do not buy gen 1 450s. They are obsolete and you will encounter maintenance issues. 450ii from a dealer can be brought up to iii but it’s costly (albeit worthwhile). I own the iiis upgraded from ii and they have given years of sterling service