seren - I use uk.camelcamelcamel.com and research what I want before the sales, so I know I'm getting the lowest price to date at least. There's not much you can do about a product being reduced even further at a later date, though forerunners tend to hold their value well. A bit too well sometimes.... the 305 is selling for nearly £200 now, and I bought mine 5 years ago for £130.
I've got the Alpkit Gamma too, but haven't had to use it yet so can't comment on the practicality. I bought it well before I needed it because I got caught out last year when they went out of stock (who'd have thought they would sell so many in December/January
).