Hi Sloggi,
No its not hard to keep clean. I use my steam cleaner to clean it (& sometimes regular glass cleaner). It does'nt get cleaned every week - with a 2yr old and working full time its hard enough to get the time to cook dinner! Its right behind my hob. I very rarely use a frying pan only for stir-fry's and I would usually have them on the front of the hob, so its mostly steam from saucepans and I leave the extractor fan on for about 5 mins after cooking (while I'm dishing food out) to give it a chance to dry off quicker.
The fact that the glass is clear, it does'nt stand out in the kitchen.