I owned one many moons ago .... it was an '89 ... fully guarded, and with a hyd thumb ....
She was a good little girl ... when it ran ..... was rather warm blooded, and HATED THE COLD ....... it could be the middle of July, you open the cab door and say the word COLD and it would not start .... and we did check everything on it from valve lash to timing, it was just that engine ... a buddy of mine had a 490D from the same era and it too was the same thing
Other than that, if you ran other excavators with the short joy-sticks ... the 290 has longer ones, which I found OK except don't use the arm rests on the seat.
It was a machine that was amazing for its size, a little rocky, could use a slightly longer under carriage, if it was a blade runner, like its next smaller brother the 70D (had one of them for a short time too) that would have made it perfect
It was a machine that you always wished it had 2' more reach, it was kinda a machine stuck in between sizes, not a mini but not a biggy, but again it could blow your mind what it'll do
Let us know if you get it .... good-luck