Have seen plenty people using them and read varying reports from good to not so good, but they have a 10 year guarantee if you have any problems.

Used a borrowed large one for our trip to Kenya last month - certainly much lighter than the hard cases we had previously used (about 2.5kg lighter when empty!!) - also actually bought a small one sized for cabin baggage - very useful on the small plane from Mombasa up to Masai Mara as it held loads of stuff but was still under the weight limit - can't comment on robustness vs time but felt quite strong - but then baggage handlers are known to manage to damage even Samsonite type cases!!!!

We have two, they have survived two trips to Goa and two trips to Greek islands so far with no sign of damage etc.
When packing it pays to put something a bit rigid in the bottom where the wheels are to stop it sagging when pulling it along.
The guarantee excludes things like bad baggage handling etc.IIRC.
Would I buy them again?
I'm not sure, they are light and appear fairly strong but I always have a worry on getting to baggage reclaim.
At present there should be some in the sales which will make them a good buy.

I've got three now one is four years old and still going strong, great for families struggling with luggage allowances.

Ive got 3 and have used them for I think 7 holidays, no problems at all. I got them BOGOF for the 2 large ones - bargain!

Got one of the four wheel variety. Use it for short haul holidays where the baggage allowance is restricted. Not sure if I would take it on our long haul holidays where we might have up to eight filghts involved. Whether it will last the twenty years my last case did I wouldn't like to say. Must say the carry handle feels a bit flimsy, and the bags bulge when loaded. Still its survived a couple of trips so far.

Must say the carry handle feels a bit flimsy, and the bags bulge when loaded

I agree, I should have put that in my earlier reply.
We always put a couple of luggage straps around the cases to try and lessen the bulging and have found that putting coat hangers etc in the external pouch does stiffen it a bit.

great minds think alike del949

I bought a small one to use as hand luggage last year and was really impressed with the amount of stuff I managed to get stuffed into it.