Blouz,
You won't be disappointed with either capsule. I built with an AMI kit using PVC Thiersch M7, AMI BV8 and Telefunken EF802 tube (same combo as Oliver used in Lucas CS-4). AMI supplied ALL the parts (body, headbasket, transformer, PSU, tube, cable, Binder connectors, Thiersch capsule, tagboards, caps, resistors, etc), which coincidentally were all the exact same parts used in CS-4. Nice! I figured Oliver had put a good amount of time into sorting out all these details, and I'm lazy, so I went with his experience. I didn't have to shop around to get the stuff I needed, it all showed up in the same box. Well, I did buy some silver coated 28 gauge Teflon wire off eBay for hookup and some silver solder from Fry's. But that's about it. And I ended up with a stellar mic.
Whatever U47 you end up building, be sure it has the ability to switch the back diaphragm off when in cardioid mode, like the original U47. You gain 3dB more output and lower noise. This is the setting I use almost all the time for vocals. I did it using a relay, the way Oliver did it in CS-4. Wow I miss that guy.
Also, when handling the capsule, use rubber gloves. It's just too easy to touch the diaphragms with a finger or knuckle, and then you have a grease spot. I also don't touch 1G ohm resistors anymore, only use surgical hemostats. Too easy to get skin oil on them. There's a thread here on building the AMI kit where I posted a layout diagram and other info, might come in handy for you.