First I'd say that the 763 to the 1845C isn't a apples to apples comparison. The 1845C will work circles around a 763. As for weaknesses, I rank the Kubota and Cummins as being equal in reliability (just my opinion) The handles on the 1845 can get sloppy and cost a bit to rebuild the linkage to the control valve. A plus to the 1845 is that you can tension the drive chains if they are loose. You should check the machine you're looking at to see if the tensioner bolt on the axle has been adjusted. If the head is bottomed out in the housing, you're out of adjustment. IF you can see threads you've still got some adjustment. The 1845C's have a dry pin that attaches the quick attach to the boom. It never bothered me but I thought you should know. Check the quick attach on the 1845 as they are known to crack. The 763 weakness is the single tilt cylinder design. They can break the boom at the "doghouse" where the tilt cylinder mounts to the boom. No drive chain adjustment if the chains become loose (lift the machine and check for drive chain play and axle end play while it's up) Depending on the year you might have to install new blocks for the seat bar to release the pedals. Steering adjustments are easy on the 763 and if there's a problem it's pretty easy to correct most of the time by flipping the blocks or installing new pintal arms. If it's me I get the 1845C because they are a workhorse. It's a mid size machine with a large frame attitude.