I went through the same choice a year ago after my second QL quit during snow blowing duty in winter. Another QL or 1862?
I have owned and adored my 1650 for 10 yrs. Have went through the motor mount and usual 'issues' but enjoy my QL's.
I bought the 1862 and very glad I did.
However, like the QL the 1862 has it's quirks. Those da$@#& plastic covers!.. and bad switches.. and wiring. Although lets be honest, the QL is not very 'quiet', and that jerky, creeping hydro.. uhhg.
Drive train is probably better in the 1862, so..
After all said and done, fixing the 1862 gives you twin smooth, 18hp, hands-off hydro WITH power steering- Ounce you've had a color tv, it's hard to go back.