so if i order one and am not happy with it i can send it back for a full refund?
If it doesn't work as designed or is faulty then of course you can. However that may be different to 'I'm not happy with it' so you need to be sure of what you are trying to achieve before deciding which route to go down.
I have used these on road and race bikes (up to 110bhp) with no problems at all. Most of the problems related on forums with these kind of fuellers seem to be from people who expect the Powerizer to somehow give them a magical power boost or to do something that it is not designed to do.
It is a simple method of adding fuel where required in order to richen the mixture, allow the use of aftermarket pipes etc and give better 'rideability' and throttle response. It won't give a magic power increase, it is not 'tuneable' and it isn't a magic pill to make a poorly set up bike run well
If you want a simple to fit, simple to use piece of kit that will address most of the lean running issues that Buells suffer from then it is excellent product and lots of people run them quite happily. It is purely designed to work with stock(ish) bikes that have an aftermarket pipe fitted, and for people that just want a 'fit and forget' module. If you decide that you want to put the bike back to stock you simply remove the module and it reverts to stock immediately.
If you are looking for something that you can 'fiddle' with or adjust, or want to go a lot further down the tuning route than just a pipe and filter, then maybe another method may be more suitable.
My opinion is based solely on the dozens of individuals who have been very unhappy with them and have posted to that effect on the board.
Don't believe everything that is posted on forums

The majority of satisfied owners/users don't post on forums but just use their bikes quite happily.