Received and just installed the Jantzen's today. First listen is excellent. They seem slightly less warm than the Mundorf right now but I'll have to give them some time before giving a final opinion.
Edit: I am 5 hours into listening. The preamp is sounding amazing. I am not sure if the Jantzens are any better than the Mundorfs. Just different. Both of them are excellent performers for the money.
I've also been trying out a new set of NOS tubes. 1961 Sylvania 6V6GTY ...... these puppies are an incredible pair. Possibly the best I've heard!
