My neighbor has a 2.5 acre lot. Of that, about 1.5 acres is lawn. He is on his 3rd or 4th year with an 18hp Craftsman and is looking for a new tractor because his is pretty much worn out. He doesn't abuse his tractor, he mows with it and then he washes it. Seems to take very good care of everything he owns. It is just too much for the lightly made tractor.
Now all that said, I love Cub Cadet garden tractors, I've purchased several of them, and still use the first one I bought. It is 12 or 13 years old, has mowed things it shouldn't have and taken all sorts of abuse. It mowed 4+ acres of my lawn for 8 or 9 years before I decided to get a mower deck for my larger tractor. But there is a difference between a lawn tractor and a garden tractor. I'm gathering you are on a tight budget and I can understand that, but I'd hate to see you beat up your Cub Cadet and regret spending the money on something that will likely disappoint you in 4 or 5 years. A garden tractor is heavier built than a lawn tractor, eventhough they both pretty much look the same. For the most part the only way to tell them apart is to try to pick them up or look for the GT or LT on the name plate. A garden tractor will last 2 decades mowing 3 acres. A lawn tractor may last you, or it may get pretty tired long before you think it should. It is far more of a gamble.
If it is a really good deal, then it might be a good buy. If you can get a GT instead of an LT, I would consider speding the extra money if you can.