When I hear "top to bottom" groomer skiing I think one lift ride up one long ride down. It's going to be hard to beat Stowe for long steep groomer cruisers using the gondola and skiing Perry Merril and Gondolier or a nice long rip down Nose Dive.
Mt Snow is easy with another high-speed lift up the main face for this season. Mt Snow has great snow making with all the fan gun trails and several nice top to bottom blue square picks perfect for GS cruising. North Face is shorter and steeper.
Stratton is harder to ski top to bottom runs since it was originally designed with an upper and lower mountain. The mountain has a large plateau 2/3 of the way down that forces you to schuss and pole to continue your ride down. When they added a Gondola to the summit they created a duel fall-line super trail and ruined two great classic ski runs Rime Line and Standard. You can also ski top to bottom down Liftline but you do have a long run out at the bottom.
That all being said I do my groomer GS cruising during the week when it's safe for all involved.
My VT List:
1 Stowe 2100
2 Mt Snow 1650
3 Stratton 1750
On Stratton's Rime Line in 1986