I usually burn Verbatim DLs only but I recently found some Intenso x8 DVD+R DL at an very good price, so I bought a spindle of 25 for archiving some game backups. Media code is RICOHJPN-D01-67. With both BCDC & BCFC firmwares the writer recognized them as x2.4 discs. Only after I loaded BCHC they were recognized at their full nominal speed of x8, but when I burned a sample the writer only managed x2.4... Quality is decent as you can see from the following graph, my 1650 has given me quite a few DL coasters when I was experimenting with cheaper media, so I'm happy with these results. Still, my Pioneer BDC-202 Blu-Ray reader/DVD burner combo (firmware v1.07EU) can burn them at x4 and with slightly better quality results (I include that scan too for comparison).
I'm pretty impressed with the Pioneer, it produced consistently decent burns with every kind of cheap media I threw its way.
First graph is the 1650@BCHC@x2.4 burn, second is the Pioneer@v1.07EU@x4 one.