sledgehammer wrote:personally i have cornie kegs for my cider but if i was starting again i would buy sankies now
Why would you now buy Sankey?
I started off with Pepsi type cornie kegs, and recently got some A-type kegs (same as Sankey but a slightly different coupler), so I have both.
Things you should consider are;
Are keg dimensions an important issue in your setup?
What's the cost of the keg + couplers.
Do you want to be able to easily open the keg to clean, or dry-hop, clarify, sweeten, flavour etc. ?
From using both types of keg, these are my impressions so far:
I'd say Cornie kegs are probably cheaper (keg plus couplers), easier to clean and easier to make in-keg additions to (clarifying agents, hops, spices, sweeteners/flavours for cider etc.) as they are easier to open, they are easier to purge or de-gas too. The tall slim Pepsi kegs also fit well in my fridges as they take up less foot-area and the couplers sit very low. Sankey couplers are rather tall (they can add 4-5 inches on top of the keg height) which can cause difficulties if height is a restricting factor. Cornie kegs are also easier to perform a quick carbonation by shaking under high pressure. To do the same with a Sankey requires you to block the product line of the coupler, possible to do but a bit more hastle and risk.
Where the Sankey are better is, it's all metal so no rubber top or base ever comes un-stuck, they are also slightly larger volume (18.9L vs 20L I think), they seal much better than a Cornie which can suffer from leaky o-rings (and this is probably their main advantage), but de-gasing is a bit of a hastle if you over-carbonate them. The coupler is also fitted with one-way valves so no liquid can get into your gas line and no air into your beer line. Sankey or A-type etc. are commercial standards, so if you want to serve your beer/cider at a function then Sankey might be easier, although there are a number of types (A, S, M, D, U .....) so that's not guaranteed.
A final note; Sankey kegs are designed to be filled under counter-pressure with an already filtered and carbonated finished product, and then to prevent tampering once filled. That's not necessarily what's happening in the homebrew environment.