RicohJPN R01-02 is a very common and sold under a variety of brand names at different price levels. The quality varies somewhat, but they will all burn at 4X on a 411/451 and 8X on an 811/851.
Office Max had Arita 2.4X DVD+R on sale last week for $40 after rebate. It was good quality RicohJPN R01-02 and burns well at 8X.
It is frustrating when a brand like Memorex changes discs without changing the label.
Some people have been able to hack firmware to get 8X burns on 4X CMC.
But most everyone gets decent burns on the Ricoh, assuming they are using recent firmware, the latest patch on Nero -- 126.96.36.199 -- and everything is set up correctly.
If it's a player compatibility problem, try using the bitsetting utility from the tools thread on +R media.