Two years ago I was thinking about a replacement to. I came across Cub Cadet and John Deere. After doing some research I decided to buy the Cub Cadet and I'm totally satisfied with it. It was pricey though, but that's because I also got 42 in. with a 3-stage snowblower attachment as mentioned here. Both the tractor and the attachment are sturdy and suitable for each season.

You can never buy too much tractor, just depends on how much you want to spend. I've had (1) Cub Cadet (maintenance headache), (1) Kubota and (2) John Deeres. I personally prefer the JD brand but not the ones you buy at the big box stores like Lowe's. Those are actually pretty dumbed down units with thin moving decks and consumer grade parts. The tractors are the JD dealer are considerably more robust (and more costly). As long as you are just mowing, a light duty unit will work, but as soon as you begin towing weight or using ground engagement equipment like an aerator, then you need a Garden Tractor, not a Lawn Tractor. You have to decide if it's worth the extra cost for a Garden Tractor - they do hold up better over time and take deck strikes much better. I currently have an X500 series in Northern VA for 1.5 acres and use both drum seeders and an aerator with it, One feature I would encourage you to get is the rear diff lock, because that means the difference in getting out of a wet slope or becoming stuck and fetching a 4 x 4 to pull the unit out. Good luck. - Duane C

You might also consider a used X series tractor if cost is an issue. I have a big Deere dealer (farm country) that has dozens of trade-ins that they auction every spring after working on them during the winter and getting everything fixed up.

Sounds like they have replaced the D series with a new E series, and I don't know anything about them, BUT:

I bought a D125 about 3-4 years ago, got it at the dealer instead of the big box, and they assembled and delivered it free (for the same price as the big box store). I think mine has a 42" deck but the 125 has a larger motor than the next model down (D120), it's a 22hp twin cyl. Sounds like it is comparable to the E130. I can recommend the larger engine option especially if you're mowing a large area with slopes, hauling stuff, etc. The engine has been very reliable so far but it doesn't have many hours on it. Hydrostatic transmission is great, I just hope it holds up, but only time will tell.

BTW if you tend to get stuck or lose traction on steep hills and don't go for the fancier tractor with rear diff lock, you can put some ATV tires on the rear. I did that on my old Craftsman and it negotiates hills quite well. They are more aggressive obviously so if you are a stickler about your lawn right around the house (for example) you might not want them for fear of the lugs making dents, but I just thought I'd mention it.