I have an '05. Bought a '10 last year. TOTALLY different bike and it took a bit of time to get comfortable on the new ride. Very sensitive throttle, abrupt engine braking, feels heavier (because it's a pig)...the older gen is easier to ride.
I bought the Flash Tune interface and made a few changes. My '10 is a blast to ride at high RPM/speeds but not too fun in lower gears putting around town.
I suppose it depends on how you're planning to use the bike. I wouldn't recommend it as a commuter.
the 04-06 is my 2nd favorite looking r1, so if looks is important i wouldn't upgrade. i tend to be a sucker for new tech, so in that sense i would. i think the sound is cool, but i doubt the bike is gonna make u any faster. really comes down to personal preference and the bills in your pocket. i'd personally, wait for next iteration. should be a refresh coming up soon.
FlashTune w/dyno fuel map|RaceTech Suspension|Termignoni CF Slipons|Attack Performance Rearsets|Brembo 19 RCS MC|Renthal Clipons|Dano QS|Akrapovic Y-Pipe|520 (-1/+1)|Hyperpro Damper|BlasterX|MRA Racing DB|Gilles Chain Adjuster| MotionPro Throttle|BMC Air Filter|Graves Smog Plates|GYTR Comfort Seat|Targa Solo Cowl|Tec-Spec Traction Pads|Pazzo Shorties|GB Racing Covers|Spiegler SS Brake Lines|HIDs|Flushmounts|Gear Indicator|Sharkskinz Track Bodywork
seriously though the 04-06 guys are fanatical about their rides, most would never look at anything else regardless of performance or sound
I'd say your 100% or 99.9% on the money with that statement. I'd never sell my 06 but wouldn't mind getting a newer gen to join my 06 when the finances allow me too!!! What I'd really like to do is make a very radical fighter style new gen R1. When the time is right I'd most likely look for a nice deal on a used 09+ to keep the cost down a bit. I hate removing perfectly good parts but if the price is right it wouldn't bother me as much.