I used to have a 50mm f1.4 on my film camera. It was absolutely fantastic. Coupled with 6400 ISO black and white film it opened up new worlds. Like taking pictures in moonlight or street-light for some great effects.. brill 🙂
Yeah but you don't have to use the max aperture though.
If you shoot at say f/8, I believe it still does the focussing at max aperture then stops down for the actual exposure.
So all other thinfs being equal a f1.8 should autofocus faster or at least more reliably than a kit lens, because it has much more light to calculate the focus from.
The nifty fifty is a sound (and very modest) investment for a beginner. Mine is on the camera more than anything and seems to produce brilliant pics despite me being really quite rubbish!!
Kerso (who runs flash camera) will do MUCH better prices away from Ebay. He operates on many phot forums and is consistently rated as a good seller, I've had two lenses off him. He'll even provide UK receipts for cashback claims if canon are running offers.