From what I've been reading online, glass is far superior to canvas, with more vivid colours, and the colours last longer (less prone to fading from UV).
30x45cm (12"x18") - $44 Save $44
40x50cm (16"x20") - $62 Save $62
50x75cm (20"x30") - $94 Save $94
For comparison, the 20"x30" is $199 @ HN
Good prices. I wouldn't say glass is "superior" however, more like different. Some things to be aware of:
1) You need a higher resolution photo; glass is less forgiving.
2) Glass photos can appear a bit more saturated than canvas, you may want to tone it down a shade.
3) Glass is, needless to say, much much heavier than canvas, so think about how and where you're gonna hang it.
4) Be careful not to over sharpen images for glass - you'll really see it on the print, whereas canvas is a bit more forgiving with less than perfect photos, in my experience.
Having experimented lots, canvas is still my favourite for large and/or everyday prints; metal remains my favourite for high resolution or smaller images that I want a real pop to. It retains the lightness of canvas with the aesthetic qualities of glass.
That said, absolutely nothing wrong with a glass print.