I have a '14 Zee 2 48" with a Kawasaki engine and really like it. It is very solid for a residential mower and the cut is superb. Other than the engine the '15 Zee 2 is the same. It also has the serviceable Hydro Gear ZT-2800 transaxles where I believe the Gravely ZTX42 has the EZT sealed transaxle.
Each has there good and bad points but the DC has served me well.
Dealer is offering a pretty good deal on a Compact-pro 44 for an extremely good price and I am very tempted... although I really don't need the commercial mower now, it may come in handy in the future. I can afford it, but not sure I should do it!
If you can afford the commercial mower then I would do it. You feel the difference when it's easier to use, the job gets done faster and you can move on to the next task, like sipping a cool drink around the pool. :drink: