Thought I had read recently on here that some have been really disappointed with their R6 conversion, and, if my memory serves me well some have gone back to the original Yamaha shock.
I went the Nitron route and am very pleased with that but it's premium price you will not get any change from 450 quid.
If the R6 shock is so good why are there so many almost new ones up for sale, it seems folk are removing them and fitting something better because they are not satisfied with the R6 performance.
Despite buggering off to the bloated monster which is the FJR1300, I find myself back here again defending the merits of R6 shocks on Fazers
The original idea was Luke / Devilsyam who came up with the conversion for the FZS 1000.
In 2013, I took this idea and applied it to the FZS 600, since I had been forced to downsize, yet found both front and rear suspension to be mediocre
http://foc-u.co.uk/index.php/topic,8167.0.html It is true that the shock is not ideal for the FZS600 ...because it's ideal for an R6. However, these shocks have a huge amount of adjustability for an OEM unit, so it's possible to adjust them until they suit the likes of Fazers. Because of the linkage unit, very little modification is needed if you're going to fit one to the 1000, but conversion for the 600 is much more involved (replacement heavier spring, top-hat spacers, top bolt and dogbones) and therefore more expensive.
When I bought my first experimental shock back in 2013, it cost me £44. Unfortunately second-hand R6 shocks are no longer sold at such giveaway prices, and now sell for 2 - 4 times that value. Given that the conversion parts for a FZS600 cost close to £100 (unless you can fabricate your own) then the cost for a converted shock becomes a bit more expensive.
I am aware that Luke / Devilsyam has almost certainly sold 200+ shocks to 1000 owners. I myself have converted 50+ shocks for the 600 owners. They have been used on many other Yamahas such as FZR600s, Thundercats, TRX850s, not to mention other Japanese manufacturer bikes. There are so many R6 shocks for sale because they've been taken from bikes being converted to the racetrack for Supersport 600 duties. Furthermore, they are a cheap alternative to the non-rebuildable OEM unit, they can fit many other bikes and can usually be re-sold for the same price that you bought it for.
Comparison of aftermarket shock prices with features that are closest to the R6 unit:
Converted R6 unit £200 (separate rebound, high & low speed compression adjusters, no ride height adjustment)
YSS £295 (no separate high/low speed compression - compression & rebound ratio is linked, no ride height adjustment)
Hagon £359 (no separate high/low speed compression - compression & rebound ratio is linked, no ride height adjustment)
Bitubo xze01 £429 (no separate high/low speed compression - compression & rebound ratio is linked, no ride height adjustment)
Ohlins £478 (no separate high/low speed compression - compression & rebound ratio is linked, no ride height adjustment)
Nitron NTR1 £438 (no separate high/low speed compression - compression & rebound ratio is linked, ride height adjustment)
Nitron NTR2 £612 (separate compression & rebound adjustment adjusters, ride height adjustment)
As for the likes of aftermarket units, I can actually make that direct comparsion. When I had my Fazer 1000, I had both a Nitron shock (NTR2, mid-range version which is now £732) and an R6 shock. Subjectively, I would say the R6 shock was 90% as good as the Nitron, which pained me at the time as I'd splurged £562 on it back in 2010.
Finally, out of all the units I converted, I only heard of serious issues from one person and that was because the replacement spring was too heavy for his weight. I am now curious - can you point me to the disappointed shock owners as I'd like to find what their issue(s) are and may be able to address them?