I did find dependency conflicts all too common on Gentoo, and keeping the system up to date was a frequent struggle. I've not had any major issues with Arch recently, and any that occur are usually fixed by doing a full system upgrade, but they do occur from time to time. I'd be interested to see how SUSE differs.
One thing I've noticed when doing a quick bit of reading on your Wiki - it sounds like you can't update Nvidia drivers from the package manager in Tumbleweed, and it has to be done manually. It also sounds like this process has to be done any time you update the kernel or X. This sounds like quite a pain - manually installing the nvidia drivers isn't exactly complex, but it's a number of manual steps that I'd rather not have to go through outside of the package manager every time I do a system update. Am I missing something here, or is this the case?
It also sounds like it supports installing with sysvinit rather than systemd, which is a rarity these days, and might appeal to some people.