I think you will find no one wants or likes the dynojet, Ivan's all the way, I believe the dynojet works best at higher revs loosing out in the midrange, Ivan's works everywhere and fixes other fuelling issues that dynojet doesn't.
Succinctly put.
The DJ kit needles have exactly the same profile (single taper) as the stock needles but are fitted higher in the slide. Smaller main jets and adjustment to the mixture screws are the total of what you get. You could achieve the same top end gains yourself by shimming the stock needles higher and fitting smaller mains but - as solorider said - you'd likely encounter fuelling problems at part-throttle. I've removed several DJ kits and replaced them with Ivan's kits and the owners have been delighted with the difference.
Ivan's needles have 5 different taper angles along their length to optimize the fuelling at any throttle setting. There are other elements to the installation which contribute to the end result. You can read more about it here:
http://www.cartestsoftware.com/fz1/jetkitinstallation.htmlThe reason many won't have heard of Ivan is that he only does tuning kits for about 20 or so bikes. The amount of R&D time he dedicates to each model is therefore enormous by comparison with companies that try to cover the whole market.
Ivan's Slip-On kit (ie, stage one) works better with the stock air filter and no airbox mods. To get the full benefit of a less restrictive air filter and exhaust, you'd need to go the Full Monty route (ie stage two) which includes mods to the airbox lid and the intake stubs.
If you're reasonably competent with your toolkit, you can go the DIY route. Expect it to take around 4 - 5 hours, including synching the carbs afterwards. If you are considering giving it to a dealer or bike mechanic, budget on 3 hours labour for a Slip-On installation. They probably wouldn't know what to do for a Full Monty so expect that to run another 1 1/2 - 2 hours for research and the additional mods. A lot of dealer installations aren't done correctly because they either take shortcuts to save time or miss out parts of the process because they think they know better than Ivan - they don't!