Well chaps, just had my first ever DE shave with the lovely Muhle R89, and i can't express how fantastic it was. I took my time with it (plus i had a month's worth of growth to go through too!), and just did my usual prep. The result? Absolutely zero razor burn, my face feels brilliant and i didn't even knick myself once. In my near 15 years of shaving, that was the single most enjoyable shave i've experienced (no doubt helped by the sheer quality of the R89).
Used an Astra blade for one side of my face, and a Gillete Super Stainless 7 O'Clock for the other; i preferred the latter, but both were more satisfying than any cartridge i've ever used.
Will probably never touch a cartridge for the rest of my life, and cheers for the advice on where to start - i'm an instant DE convert