I have a L3901 the FEL and love it so far. I use mine mainly for mowing about 6 acres but I also will be using it for maintaining a 600' +/- gravel driveway.
I originally just added the machine to my homeowners insurance but then decided to get the Kubota insurance instead. They charged me $11.65 per thousand for the plan per year and it covers a lot more than the homeowners policy I added it to. I think it's worth the money.
One thing to mention I originally purchased my tractor with the R4 tires but after using it for about ten or twelve hours I noticed I wasn't able to add chains because there wasn't enough clearance between the tires and the inside of the fenders to clear the chains. I also added the upgraded 3 point lift arm slide links to replace the turn buckles that they put on it new from Kubota and found it hard to attach some 3 point attachments because the R4 tires wouldn't allow the 3 point arms to open wide enough to clear the pins. All the problems were solved after the Dealer swapped the R4s for a new set of R1s with the rims setup for the widest stance they could give me.
As far as weight I did have the tires loaded but needed more weight when using my pallet forks so I also added the ballast box Kubota offers it weighs right around 1000 lbs and works great when lifting and carrying max loads on the forks.
I thing you will be happy with a L3901 if you decide to get one.