Problem with cheap rotary selector switches?

So, goldpoint sell rotary selector switches for around $65, DACT sell similar, but you can pick up switches with the correct number of positions/poles/decks for under £20 (http://uk.mouser.com/ProductDetail/Electroswitch/C4D0406N-A/?qs=sGAEpiMZZMvNbjZ2WlReYqOqgxm428ccwnM2TEDe1Ko%3d) and as little as £5:
http://uk.mouser.com/ProductDetail/Alpha-Taiwan/SR2921F-0206-19R0B-E9-S-W/?qs=sGAEpiMZZMvNbjZ2WlReYnqYHrQfuERsVYNhUxQIdK0%3d

Are there any particular reasons why you wouldn't use these instead of the more expensive varieties?

I use Electroswitch C4's. It is a high quality switch. They are physically larger than a Grayhill 51 series or an Elma 01 or 04. They also have a stiff feel to them. Other than that they are built very well.

Well thats good to hear...but I don't understand, why so much cheaper?...it's about 3 times cheaper than the switches goldpoint sells, which I believe are elmas...

You are comparing a 12 position switch to a 24 position switch. That's the big reason. Another one is that Goldpoint is a reseller that has aftermarket PCB's integrated into the switch. Try comparing an Electroswitch 24 position switch with an Elma 04 or the Electroswitch C4 with an Elma 01 series. The prices are closer but Electroswitch is still less expensive