I've got the Hartmann 7R aluminium case and it is great.

Glides effortlessly, and I got it in a sale for £400. I thought it was worth it because I go through a standard Samsonite case every 18 months. I'll keep the latest samsonite for other things.

Visually, I think it looks nice, and I think that aluminium cases can take some wear without looking shabby (shabby chic).

I always find it is better to go for a mid to top of the range in any brand rather than the bottom of the range in an expansive brand.