Petr - Here is the intersection which creates the fillet problem in Rhino. I made an R1 pipe, and then intersected the pipe with the box/cube. you can see there are 3 gaps in one of the curves, which is causing the broken fillet surfaces. Manually the curve can be repaired, then trim away the surfaces between the curves, then create a blend surface to fill the gap. but it's a pain :( ...I hadn't noticed any differences between Rhino/Moi fillet results because i very rarely use primitives for modeling. Most of my work is more semi-organic, and comparisons of Rhino/Moi fillets had similar results on my models. Oh well, it's good to know i can use Moi to assist Rhino in this way.

Also, I read a post somewhere that speculated Moi might be using the same kernel as N-Power. Don't know if it's true or not. But, it may explain any similarities between fillets in Moi and Power Solids...

jonah