On the flip side, I've gone through over 200 of the large tracked letters, and I have only had one issue so far (buyer said it wasn't delivered despite being marked as delivered, it was kind of an iffy case though, TBH). Most of my delivery issues over the years have been with tracked parcels (late express deliveries, delivered to the wrong address, MIA for a couple of weeks, etc).
I think the tracked large letters are excellent value for items that can be sent in them (even with the recent price increase), if only for the fact that by comparison, a 250-500g untracked large letter is $5 with nothing but delivery included. If you then want to add tracking to a large letter of that weight, you have to pay over $4 to get it, and the only thing that extra gets you that the pre-paid tracked envelopes don't, is signature on delivery (which many people find annoying, anyway). So, for roughly the same price, you get tracking and insurance (on that note, compensation may be payable - up to $100 - on any undelivered letters). For smaller weights, I still feel the value is there, because to pay for registered on a <125g letter, the cost would still be over $6. (I actually buy the tracked envelopes on eBay, when a 10% code can be applied).
To get $100 insurance on a parcel, you have to add $1.50, so to compare the costs of the services, you'd need to compare them with $100 insurance included (though, many sellers can get discounts on this through My Post Business, eg a 500g satchel with $100 insurance, to an interstate metro location, would cost me $7.97, and I use priority on every letter I send so the cost for one for me is 50c higher than those who don't use priority - currently, with the last lot of envelopes I bought, one costs me $4.84 to send via priority, so over a $3 difference there, and about a $2.50 saving when I have to pay the new price).
Only small letters are required to be flexible, so this isn't a consideration for the large letters (they are made from rigid card themselves, and should not be going through sorting machines). They aren't suitable for everything, of course, and I still put my items in a bubble mailer before putting the items in the tracked envelope (unsealed, so it can at least be re-used by the buyer 🙂 ), anything I use the flat box mailers to send as a letter, can't go in a tracked letter as that will take them over the 2cm restriction.
The only thing I wish is that they had a C5 large letter option. The large ones are overkill for some items, and don't fit in to a lot of letterboxes.
