This question is opening a can of worms. It's like asking a random guy what's the better truck, Ford, Chevy, or Ram? But. I will give my input as I have gone through multiple mowers and other lawn equipment and have very strong opinions on some of the better known brands.
First, it is essential that you get something that has a good service department relatively close to your house. If you buy the best of the best and then have to haul it 80 miles to get serviced when you need something you will come to despise it. Second, you have to ask yourself, what kind of lawn do I want? Do you want a highly groomed lawn that requires a weed and fertilizer program and looks like a golf course, or do you just want a lawn that you cut and keep clean looking. The difference between those are $. If you just want to knock down the tall grass and weeds then just go to Lowe's or HomeDepot or some such and get a pressed deck Hustler or JD yellow deck and be happy. Remember weeds grow faster than grass and you'll mow a lot more often but you won't be out $$. I think one of those options would last 10+ years with proper preventative maintenance and care. Now, if you want a beautiful lawn, then it gets tricky. First and foremost you will want a commercial grade mower that will be several thousand dollars more than those options. You will also want a welded deck instead of a pressed deck (with exception of JD's 7 iron pressed green deck, more on that in a minute). Just Google welded deck vs pressed deck on ZTR's if you are not sure what I'm talking about. Next, what is the terrain like in your yard. Do you have flat open space or do you have trees or other obstacles and uneven ground. Makes a massive difference. If you have flat open ground and wide gates go with 54" or bigger. However, anything other than open flat space stick with 48" or smaller. It will take more time to mow but your cut will be more pristine. On uneven ground one side of your mower will be higher than the other side which transfers to the deck and you can cause gouges in the lawn. Smaller deck means more cut time but prettier cut. Now for brands. This is my list after years of experience.
Tier 1 (best groomed cut)
1. Exmark E series or up. By far the most superior cutting deck on the market.
2. John Deere ZTR any model with Green colored 7 iron deck. Usually only available at JD dealership as John Deere models at big box stores with the yellow decks are not true JD's
3. Scagg. Any model above Turf Tiger
Tier 2
Toro. Commercial grade
Ferris. Commercial grade. Smoothest riding of any ZTR
Dixie Chopper. Same as above
Kubota. Commercial grade
Tier 3
Everything else
Wow this is becoming a novel. Lastly I will say. Get an Sthil weed eater with an exchangeable attachment boom. You will have access to multiple different tools at a small cost after initial investment. Also, don't forget a push mower to compliment your small areas. Honda all the way on a push. Sorry for being long winded