The refurb sale right now does have a nice selection but as a trade off, most of the lens are only 15% off. They regularly have 20% sales and once or twice a year have a 30-35% off sale (they even have 50% off but that is typically only for the refurb older kit type lens).
The quality of the refurb lens/flashes/dslrs I've purchased (about 5-6) from canon have been just fine. But getting any specific lens you want can be very difficult. If you need your lens now, you may want to just keep the one you ordered. But I recommend checking the refurb regularly and signing up for their pita email distribution just so you'll get word of the sales.
Fyi, the canon powershot refurbs are very hit & miss. If you ever need to purchase one (as a gift or pocket travel camera, etc) I can't recommend buying thru Canon. I'd recommend just picking one up on sale somewhere else.
PS: **Don't trust the reviews on Canon's site. They filter them pretty heavily & won't post anything that gives their service a negative hit. They rejected two of my reviews of the refurb products I bought from them.