Rocktron made good gear.
The only downside to it is that they were less popular, so anything you encode with Rocktron n/r won't likely be able to be decoded elsewhere. If you don't plan on shipping your tapes out to another location, not such a big deal, BUT, if your 180 goes belly-up it'll be harder to find a replacement to be able to playback your Rocktron encoded tapes.
Don't recall the n/r convention employed by Rocktron, but do a search on this forum and you'll likely get the scoop. I know its been discussed before.
$45 is good, but I'd be spending my money on dbx Type I.