The Zuca cart is fantastic if you play in a lot of tournaments, or if you just like having a ton of discs to throw on every hole (great practice), and don't want to carry around a 50 pound bag on your back.
When I first got my cart, I emptied my large disc golf bag and the Zuca cart was barely half full! I went through my stashes of discs to find additional ones to haul around simply because I could. When all was said and done I am able to hold 36 discs. I put four discs in the the side pockets (three putters in the flexible elastic side, and my trusty Orange Justice in the other side). This makes quick access to these frequently thrown discs and they are high enough up that you barely have to bend down. I also hold a sweatshirt in the bottom side compartment below the upper rack of discs, and a thin rain jacket in the same side pocket below my three putters. It's super convenient to get your discs out of the cart, especially the top rack.
I have a seat cover and a handle pouch that is great for snacks, my dirt bag and mini markers. It's also super handy for storing the cell phone and keys. It also holds my disc gator and an umbrella when needed without any additional inconvenience in toting around. For a big drinker like me the ability of holding two large water bottles is also a must.
The best part about the Zuca cart is that it is a super convenient seat wherever you go. During an incredibly rainy tournament I actually taped my umbrella handle to the cart handle and had a permanent umbrella holder. Pretty convenient when you need to write on a scorecard or just dry your discs while holding an umbrella.
Normally I don't take many back up discs in my disc golf rounds because I rarely lose discs. However, when I played Olpe Lake at the Glass Blown open I was sure glad I had all the backups after losing 5 discs in a single round (did I mention that I HATE that course).
Compared with the Delta Disc golf cart, the Zuca is a lot less expensive, holds a lot more discs, and has a higher seat (which is very nice for non midgets).
Overall I love the Zuca for tournament and practice play, but can't give it a 5 star rating because it has a few downsides. While it holds a ton of discs and everything else you want for a tournament round, compared with a disc golf bag it's pretty bulky, substantially heavier, and much more difficult to haul around and get in and out of vehicles. I drive a Toyota Corrolla, and while I can fit it in the trunk, I have to to lower the handle and remove the wheels which is a hassle.
The Zuca cart also provides more hassle than its worth when playing a super mountainous course. It's not a lot of fun to have to carry that beast around when wheeling it is not an option. My last complaint with the Zuca is that it's a super pain to pump up the tires. I got a flat and neither of my two bike pumps fit in the tiny wheel area.
If you can avoid flat tires, like to carry lots of discs, play lots of tournaments that are on mostly open flat terrain, I highly recommend investing in a Zuca.