I've been using Fastway for over 9 years and rarely have issues.
They are certainly one of the cheapest ways to freight items, especially their 1kg, 3kg and 5kg SATCHEL delivery rates which are often cheaper than Aust Post standard rates including 'special' eBay rates.
I've never had a parcel go missing and never had a breakage reported with Fastway.
Some more distant and remote areas take a little longer than Australia Post - usually places where Fastway don't have agencies and have to rely on local couriers to complete the delivery. However I've never had Fastway go over the maximum estimate of delivery days. They have come close on a couple of occasions but it's almost always because of a 3rd party delivery agent.
If you do an online quote before the delivery you'll get an estimate of cost and delivery time to the location. I include as much postage/delivery info as possible in my listings, including prices and estimated delivery times. For larger/heavier items, a freight agency that is cheaper delivering to one location, may be more expensive to another. In this case I include a chart showing costs for Australia Post, Fastway and TNT to the various areas of Australia. Wherever possible, if Fastway fees are lower than Aust Post, we offer delivery via Fastway. I find if the customer is well-informed. they can choose the option that best suits them, and they can do it without having to make contact with me first. In the majority of cases Fastway is the cheapest option and the one most selected by customers. Customers generally will choose the Fastway option unless they have a PO Box or are in a location where cost of delivery via Fastway is prohibitive. A large percentage of our sales are delivered via Fastway. We have a 5-star rating for 'Delivery' and our eBay store feedback is full of positive comments about the fast delivery service we provide.
The other thing I like about Fastway is that you can easily locate the delivery drivers online using the destination postcode. I find this really helpful at times, for example like when a customer tells you AFTER you've sent the parcel that they want it left by the back door. A quick search online gives the driver's name, happy smiling pic and timetable. I've had contact with a few drivers over the years and all have been great to deal with.
With the recent changes to eBay fees, we've started offering Free Post on as many items as we can. Offering Free Post with Fastway satchel delivery on certain items has actually brought the item price down and increased our sales. Some items we'd never sold before are now selling regularly!
Based on my experience with Fastway over almost a decade, my opinion is you'd be doing you and your customer's a grave disservice by not at least offering Fastway as a delivery option.
