Most RGB work in the same way. The difference is mostly in software and if you can synchronize it with all other RGB in your PC.
The main problem with RGB effect are semi-transparent covers which give better or worse light/colors and sometimes the way how LED covers/bars are installed (sometimes a big part is covered by a holder mounted to the heatsink).
- G.Skill Royal is the best looking but also the most expensive. Different heatsink and transparent bar are not really worth premium price over Trident Z RGB.
- HyperX Predator RGB with new software works good (they had a delay with soft release) and you can find it quite cheap. It depends on store and country. For example in the US price is not the best but in EU it's one of the cheapest, good looking and well overclocking RAM.
- Ballistix Tracer looks great but is not available in higher speed and you can expect Micron IC there so everything from average to well-overclocking chips.
- Patriot/Geil/Team Group/Corsair/ADATA and some others ... for me not the best lighting effect, part of the RGB bar is covered, random and often cheaper IC as someone thought that RGB will cover everything else, some kits in weirdly high price, some kits are of course good
If you don't really need 5GHz CPU clock then I think that better idea can be Zen 2. We still have to wait for premiere to see the real performance. Personally, I wasn't happy with 9900K in a daily PC. I had some fun while benching it on dry ice but it was way too hot and was not really overclocking on ambient cooling. When I was done with benching then I sold it and I was using 8086K till now.
Both Intel and AMD work great with DDR4-3600 CL16 kits (for AMD it depends on the motherboard but Zen 2 will support that without issues). All of them except maybe new Ballistix Elite, are using Samsung B-die and let to OC past 4000 (usually up to 4400-4500).
Almost all 3200 CL16, 3400-3866 CL19/20 kits will be on Hynix/Micron and won't OC high so no matter what you pick then try to stick to 3200 CL14, 3600 CL16 or 4000+ memory kits.
Summary:
my pick for the best effect and good IC - some kits from G.Skill Royal series like 3200 C14, 3600 C16, 4000+
my pick for the best price/effect/OC - HyperX Predator RGB
if we were talking about non-RGB kits then I would add something