Hard to beat the x7-series as a full function garden tractor. Large, powerful, capable, 3-pt hitch option, rear/mid/front PTO options, AWD, AWS. Couple of things to keep in mind as you look:
Somewhere in the prior 'generation' of x7-series (back when the models were x72x (gas) and x74x (diesel) they changed from mechanical four-wheel drive to hydraulic AWD which continues with the current x73x and x75x generation. The hydraulic AWD is very highly regarded as a system that just plain works well. Being full time with no need to turn it on or off and designed so it transparently assists as needed I highly recommend getting a tractor with this on it. It has essentially zero negatives, beyond initial costs and a bit more maintenance but I find it invaluable.
Seriously consider whether you need AWS. The non-AWS models already have a pretty tight turning circle and can mow pretty closely around trees, etc., especially with the 60" deck. Avoiding it will open you up to a lot more models, availability and price points, especially in the used market. And there are fewer moving parts to potentially cause issues.
Both diesel and gas models are very capable. Diesel tends to hold value a bit better, but has a higher initial cost. It does use less fuel though (0.8-0.9 gal/hr at WOT versus 1.2-1.3 gal/hr for gas). Not really a big cost factor, but for me I can mow my entire 7 acres on one tank of diesel but I'd have to stop and refill if I had a gas engine and that is meaningful to me.
The earlier generation can use a factory loader and is more compatible with the 7-iron decks, if that matters to you. The current generation can use an aftermarket loader and may be able to use a 7-iron deck but with restrictions (lift height reduced, not direct fit, deck warranty voided).
Yes, the current generation of x7 doesn't have a diesel AWD AWS model like the x749 because the weight would have caused it to require a ROPS.
Rob