As far as I know the Blum's have always been considered te gold standard, but I've not tried the KV's nor have I heard anything wrong with them.
Which ever you choose, do check on how they are installed. The dimensions of the drawer, bottom and side clearance, are fairly critical to proper installation. Don't know about the KV's but you can get full instructions for the Blums on their web site. I've found it best in the past to build new boxes for drawers and just reuse the front screwing it to the new box but then I'm a hobbyist, not a pro.
Here's the instruction sheet from the Woodcraft site on the Blums Tandems, you can see how much tolerance you have.
Might want to just get one set of glides to try. May well need mounting brackets depending on how the cases are built. I also found a right angle drill/driver (Bosch) a good tool for this kind of project.