Originally Posted by QuickPuppy
For further clarification:
I'm currently using a New Holland TC29 pulling a 6' finish mower. The yard ranges from areas around the house that are almost 100% St. Augustine grass, to mixed weeds and grasses (dollar weed, clover, etc.), to a pasture type area that is clover and I think Bahia. The bahia (thin and wispy looking) is what the current mower has the issues with. It doesn't look that thick but it sometimes bogs down even when creeping in 2nd or 1st gear. (About half walking speed.) We try to cut at least once a week during the growing season but at times it probably needs it twice a week.
If it is Bahia it will have a Y shaped seed head on the end of the stem. It can be tough to cut clean in one pass when the stems get tough in the dryer, hotter parts of the summer.
Do a Google or Lawnsite search to try to identify which grass it is that you're talking about. IMO, if the majority of your "toughest to cut grass" is Bahia then your mower should be the one that will cut that the best in one pass.
Of the three mowers that you've listed, I would lean towards the Scag, IF that is indeed Bahia that you were talking about.
I cut mostly Bahia covered yards/lawns, with also some Dallis grass areas and some Bermuda, Zoysia and St. Augustine areas, as well. All of the mowers that you've mentioned will do great on all but the Bahia, but they all will do an acceptable job on that, with the Scag doing the best of the 3 based on my experience with Scag Wildcat (61"Velocity +) deck and JD Z920A (I think) with the 54" 7 Iron Pro Deck.
While I've heard/read a lot of complimentary remarks about the Toro Commercial Z's, they usually didn't mention cutting stemmy type grasses like Bahia with them either, so I can't say for sure that the Toro would not do as well as the other two on that stemmy grass that you mention.