I have another kit from Microphone Parts.com. I have no affiliation with that company but have found them to offer outstanding products at very reasonable prices for the quality of the sound, the kit and building process and compared to other mics that are much more expensive.
I won a contest and built the MXL 990XL kit with the RK47 capsule and it sounds fantastic. I took my time and the mic worked on the first test, the build manual is flawless. All you have to do is follow it.
That mic has a transformer that generates second order harmonics and the capsule has a smooth but subdued high frequency response, it sounds fantastic for vocals.
My new kit is for a Groove Tubes GT-55 mic. I got the RK12 capsule and the T84-55 circuit board with the T65xf transformer. This will generate the highest level of second order harmonics of any Mic Parts kit.
That and the MXL kit I already built should cover my "vintage mic tone" needs.
Eventually I will build another kit with their RK87 and transformerless circuit board, that will be my clean sounding mic.
I am prone to using two mics at once for vocals. Align the fronts of the capsules as well as possible and record on separate tracks. One vintage and one modern will provide options when mix time comes. I'd probably do the same when tracking various instruments. Not inexpensive but not really high prices either, figure you'll be out under $400 per mic if you already have "donor" mics. They make a LOT of different kits for upgrading crappy, cheap Chinese mics into something really good.