Just paid CAN$20.38 on a US$49.00 purchase from Massdrop. $10 brokerage fee, $6.63 in duties, $3.75 in taxes.
The problem is, Massdrop uses DHL, rather than USPS.
The difference: DHL systematically assesses customs charges for parcels entering Canada. USPS/Canada Post often waive taxes and duties if the amount is small. And if they waive taxes and duties, then they also waive the brokerage fee. So on average, it is a much better deal. I'd have stood a good chance of paying $0 on this rather than $20.38.
Massdrop, here is what you need to do in order to retain Canadian customers:
1) Use USPS
2) Or at least tell us that you are planning on using DHL before we purchase so that we don't feel like we've been forced into a situation we'd rather avoid.