Is it better to use PayPal shipping label or to go to Canada Post instead?

[chaldo2010]

When is it best to create a PayPal shipping label vs paying for shipping at post office?

Do I stick the blue 'Air Mail / Par Avion' stickers on the packets/parcels I mail out to buyers to Canada and US? 

If I print a PayPal shipping label, should I stick the blue 'Air Mail' stickers on the packet/parcel as well?

[kroutpick]

For any parcels, I always use the Paypal shipping labels, with Paypal, you have enterprise discount that can go up to 25%.

Each labels has the shipping method printed on it

"Air mail light packet"

"Surface light packet" etc

I don't use blue Air Mail stickers, If i choose air mail shipping and pay for, it will be sent by mail, If I choose surface service, it won't change anything to stick that blue sticker, it will still be ground.

[bestchoicebrand]

I use 'Air Mail' stickers for US air packages on labels printed with paypal. Postal workers suggested that, it's more visible.

[reallynicestamps]

Using a Paypal label means you don't have to deal with officious counter staff or wait in line.

Some PP labels offer a discount of 5% to 18% off counter prices

Making the label walks you through all the steps you must take to get the parcel delivered. (Air Mail, Customs info, value, etc.)

The label looks 'official' and professional.

Cons:

PP (and canadapost.ca) do not provide labels for letter rates. Light Packet is covered, but more expensive.

Stamps are prettier.

It is possible to buy postage stamps on eBay more discounted than the PP discount rate.

For the Air Mail stickers- I use them for out of country mail, but they are irrelevant within Canada.

[chaldo2010]

I thought CP stopped offering Surface/Ground services?