Yeah. In my experience Git doesn't handle huge trees very well. The Linux kernel isn't very big. For example, a company might have the kernel, glibc, and 30+ other large custom and open source libraries and applications in the same versioned tree, with tens or hundreds of thousands of revisions.
This isn't feasible with Git. I once let a git-svn clone run--over a LAN--for 2 days straight before giving up. Not just Git's fault, granted, but a problem all the same.
The Git solution is to use sub-modules. Whether this is better or worse is fairly debatable, but it's not practical to shift huge SVN trees over to Git.