To be honest, the main reason I chose the kraken was because I got told I should upgrade my current Air Cooler and I wanted RGB..
Totally understand if you want to change for new look - but nothing wrong with your present cooler unless it's under performing. Main problem is that it's a PITA to fit if i remember?..
Is the AIO noiser than air fans?
It's all relative - but for me yes.
I found the fans noisier - mainly due to rad placement being on an open side of case (more noise to escape) plus some of the fans on units are noisier than quality air coolers.
Add to that pump noise (on some units), dying pump noise, clicking - plus the fact they have a shelf life (pump breaking, fluid evaporating) where as a decent air cooler will last for years and years if looked after - and even then it's usually a simple fan change. For example my Silver Arrow is still going strong after ~6 years and works and looks as good as the day i bought it. Although it has it's fair share of my blood on its cooling fins as it's a bitch to fit :/.
Having said all that - AIOs have there place as they perform very well. They're excellent at what they do, simple to fit (on the whole), more working space around CPU, and if you get a unit without any issues it will last you many years.
Each to their own - i certainly don't want to put you off getting one if it fulfils your criteria as there are loads of happy users out there who would counter my opinions.
If so can you recommend anything else RGB related I can look into?
I'm out of my league when it comes to RGB i'm afraid. I build sleek, plain black boxes - no emission of light - where the CPU is essentially locked away in the dark surrounded by sound proofing - my components have a deprived existence
My preferences would guide you to looking into boring looking be-quiets, Phanteks and Noctuas (air coolers) - the be-quiets for a moody look. And then looking at creating shadows/effects within the case via case lighting/strips etc...
You can replace the air cooler fans with LED fans - but i wouldn't know how quiet these are. Someone else with more RGB experience would need to advise you there.
But, i will add i've fitted an NZXT - and it did look very classy. So don't let my ramblings put you off your preferred choice...