that's considered a "smooth" scan believe it or not.
it looks like your drive just reads the second layer more slowly (which i've never seen before, but it still looks alright)
you want to stay away from erratic dips.
the only surefire way to tell if they work is to watch them, but i'd be willing to guess that this will play alright in a standalone that isn't super picky.
just because you got a Ritek DL burn to READ ok doesn't mean that there aren't a lot of errors on the disc. a disc quality scan would be the only way to determine this.
without watching the disc, i'd say it looks alright to me, but to check every so often. poor quality media is notorious for degrading quickly.
that way if you find that you get a poor transfer curve or if you're watching it and it skips a lot you can pull out the original and make another backup.
for more info on quality tests, transfer rate scans, and general opinions on media check out the blank media forum.