Good Morning Teachu2...about 6 hours on my GT48DXLS and as you have reported it continues to impress. Very strong...I have mowed 18"+ tall, thick green weeds and while the motor feels a bit labored it quickly clears itself and handles the weeds well. Occasionally leaves an odd standing tall stalk but with what I am mowing that is understandable. I also do not discriminate against small brush and it handles that well also.
SO far I have been stuck 4 times

Twice in wet clay as the tires "loaded up" with clay and were like "slicks". Had to pull it out...locked diff no help when traction in rear tires is near zero and terrain is uneven. The other two times I was stuck on dryer ground and the locked diff quickly supplied relief. Wet clay is terrible.
Couple of questions...
1) I have operated last two lawn tractors for over 25 years with rear wheel weights and chains...never removed either. Only stuck once during that whole time...hung up on the deck trying to cross a small stream

Dealer is brand new but thinks he "heard" you could not add chains...due to tire clearance??? It does look tight.
Are you aware of anyone who has added chains? Is there such a thing as a low profile chain?
What about better traction tires? Maybe HDAP like JD 5xx series has??
I have pretty much used in each of my mowing areas and the traction is my biggest problem...I knew that but had hoped the diff lock would be a solution. Either need chains/wheel weights or perhaps better traction tires. However, I think the wet clay would nullify other traction tires also?
2) With my use I have learned that blades/spindles and belts are often the "breaking" point as I use my mower as a quasi brush mower. I think I need to add a front end mower lift as this deck is likely too heavy for me to deal with...particularly for blade sharpening/change which I need to deal with pretty often. As long as I use blocks to support frame for safety I assume I can reach under and remove the blades for maintenance?
3) I see you changed to Oregon mulch blades. I do not bag but have no strong reason to mulch. The new mower is a monster at blowing the clippings...and does not seem to clog up at all. My concern is blade strength, holding an edge and high lift for blowing out. I know I will dull...both on heavy weeds and sticks as well as glancing off rocks, small residual stumps and dirt. I like the performance so far of the stock blades but wonder if there is a stronger version that would perform the same but maybe last longer between sharpening and other damage...ie heavier duty blades (that still throw the clippings as well).
BTW...I am actually a little nervous and watchful as I think some may have issues with damage from stuff thrown out the chute. Most of what I do has nothing to damage from thrown debris and I usually am out alone. I LOVE the power of the dispersal of clippings, small rocks, twigs etc but would not surprise me if they modify the chute in the future to deflect a bit more...or other solution.
4) Soon will be looking to do the 8 hours oil/filter change...looks like straight weight 30 will be my choice as we rarely see 90F+. No synthetic oil for straight weight I don't believe? Would not a multi weight xx/30 or 40 be a good choice? Any problems with oil filter change out? Do you have the filter number handy?...I don't see it in the Kawa manual.
I view the problems I have had with the mower...primarily getting stuck...as my usage issues. I suppose it is possible I may need to "pay up" and get either an x590 or perhaps an x7xx (with all wheel drive)...or other and mower. Perhaps I need to stay away from my clay areas...that and this has been a VERY wet year here in Northern Minnesota. Time will tell...I now know what it won't do
Appreciate reading your inputs...TMR
BTW...I have learned that even when coated with mud it cleans up pretty good with a quick hose washing and then mowing all my rough surface terrain...now clean as new (well almost)