It seems that the 3D variant cannot be used along with mudguards, the "21F" version is a tad (10g) heavier due to the unbroken leverage and all save 15g if you opt for the ti-version.

I'd assume that in terms of money saving the easiest thing is to stay away. There's sometimes a lot of magic mystery around tuning parts for people to justify their choices and spending. Personally, I am happy with the Brompton stock brakes and do not feel the need for more break power. If I felt that need I'd spend my money on brakes that are actually different and provenly offer more brake power like Magura Hydraulic brakes, V-brakes or disc-brakes (with the latter needing modifications on frame and fork). I cannot imagine that the Rideas offer additional break-power that would be worth 200€ per piece. It seems basically to be a bit of bling, mainly adding to the optics and indiviualization of the bike and maybe a tiny bit in weight but less - if at all - in objectively better break power. Better break power seems btw. not on the list of what Ridea promises for these breaks - which makes me even more suspicious that forum posts you found may be buyers trying to justify their (totally legitimate) buy with some fake objective reasons...