Thread from the dead, sadly I have not much else to do but read through, figured I spend enough time in a swag to weigh in on this.
So every now and again I live in a swag for months at a time due to the nature of my work (it's luxury for us believe me) and tried many of the options out there, firstly I'll say anything under $300 is a waste of time, another common thing I've heard is that a swag should be waterproof from the shop, not the case, as stated previously the reason to soak your swag is to swell the stitching, nothing to do with the canvas, another is that PVC floors are better, perhaps in the short term yes, being water proof from the store, however having had a PVC floor I can assure you that no repair kit can waterproof a hole again and the swag is next to useless, having had most of the cheaper brands out there trying to get out of it cheap has taught me a few things, fiberglass poles... don't waste your time even if on the odd chance you can find a replacement it will last no longer than the original and that PVC floors wont stand the test of time.
The biggest tip I can give for a swag is they do require maintenance, a good clean to remove all mud and gunk when possible and personally I waterproof after every outing, more so my OCD kicking in than a requirement, but none the less still needed.
As for brands, Darche are great, I wouldn't spend that kind of money but some of my guys have I couldn't recommend them enough, Bourke & Wills is what I've stuck with (on my second, due to preference not worn out) and I will stand by my Redgum, Jolly make great swags also, however I never had the pleasure but they seem good by all reports, Dune a brand sold through Amazon outdoors held up well but this is where I learnt the PVC floor lesson, Oztent seem to be the same as Dune and as such I would assume the same quality.
Overall, I place a 5mm high density foam cutout from Clarke rubber regardless as this helps with the cold a lot, waterproof regularly and stay away from PVC and fiberglass.
I might have to do a product review of my Bourke & wills as staying all over Aust in every weather imaginable and after four years it's still as good as new.
Edit: And as mentioned in another post Wildearth.com.au are great prices are good to begin with but buy a few things and give a little hint towards how much your spending and next thing you know another 10-15% off and free postage, these guys really are great to deal with (can't comment on product support as nothing has failed me yet, touch wood)
Regards Jezz