I also own the ML120 white fans, quality bit of kit and not sure if I'll be making a mistake if I swap these out for some RGB LL fans!
Choices, decisions... lol?
ML120s are very good fans, damned pricey too. For me, it’s not worth changing, I’d rather spend the money on other things.
Tbh I’m not that fussed about RGB. It’s nice so I can switch colours up once in a while, but I tend to go for one or two and leave it for ages; been white with blue accents for months. For me it’s just the convenenience of setting all lighting for all my gear in one program, having pre-sets I can launch at will, with temperature and flow alerts. From my experience most people play with their RGB kit for a few days then leave it as is most of the time; I think they love the idea but realise that they don’t really want their £2,000 setup looking like a unicorn has vomited on it.
Assuming you go with the Commander Pro and Lighting Node Pro, that’s already device monitoring, pwm fan control, and lighting for your desk / PC interior. Not to mention other potential colour opportunities; motherboard, ram, cpu cooler, graphics card, peripherals etc.
Just gotta decide if you want to buy into a single brand for the most part; whilst the market is finally starting to coalesce, with cross-platform control slowly being a thing, we’re still far, far away from a unified API / standard.
Serendipitously I have a fair few Corsair items already, more because that’s what I liked at the time rather than any urge for RGB or brand loyalty. Plus I’ve used Link and CUE for years; it makes sense to buy into the ecosystem where applicable.
If you’ll be using all the rainbow effects or want lots of different colours then it’s probably for you. If, like most people, you’ll set the colour scheme then leave it alone for the most part then don’t bother.
The only real benefit is single software and effect synching, but it ties you down to very specific products if you don’t plan ahead. If you can live without effect synching, then you can have one app for fan control, one for lighting and one or two for peripherals, with more freedom to pick and choose what products you integrate.