Bri, before you take the plunge, have you considered sankey style kegs? the sankey coupler is a simpler single attachment, and has much fewer perishable o-rings and is therefore much less prone to leaks and losses. And there is no dodgy lid to seal either..
the downside of the SS sankey kegs is that they are not available 2nd use that often which means paying full retail price. However there are much cheaper 'single use' options such as polykegs or ecokegs which are basically 30l pet bottles with a sankey screwtop designed for single use but ...
there have been a couple of 2nd hand poly kegs resold by brewers who have bought a couple of hunderd from a brewer and cleaned and passed on to the rest of us @ <¬£10 + pnp i think you can buy new via ebay for circa ¬£30
And the 30l capacity means you can keg a 23-25l brew in one without having to mess about with half a dozen or so bottles when you keg a 5 gallon brew in a 19l corny..
however the larger size also means you can only fit one in a standard under the counter fridge..