If you intend to upgrade in the near future, then I'd leave things as they are. It isn't going to make much difference if you have different partitions with different filesystem types.
If you want to switch to ext4 in the future you will need to format your /home partition, which means backing up and restoring. As long as you use a file backup, rather than a filesystem backup tool, when you restore your files, they will not revert the partition to ext3.
Edit: I should mention (before someone else does) that some people still don't seem to like ext4, and although openSUSE defaults to ext4, I have kept all my partitions as ext3, which has served me perfectly well up to now.