there's no reason not to install 7.0a, it's a stable system. However it's probable that you will not see any difference since fixes were generally esoteric functions that many owners never used or saw, unless you want to use soundcards. Following the disk check before upgrade will be safe but there is a microscopic chance something could go wrong (eg power failure during the upgrade) which would require a service fix, which now will be difficult, just as long as you appreciate the tiny risk involved.