There are tons of testimonies on the C1 comparing it w/ the U87 – and in some cases, people think it's better. I know a lot of people have bought C1's sight unseen based soley on my and other's reviews. The only emails I've ever received from C1 owners have been to say "thanks!".
Everyone that I've seen that's bought a C1 has been blown away. When I bought my C1, I wasn't looking for a "budget" mic, I was looking for a great vocal mic – and ultimately, I was willing to spend $2000.
In the last year, SP has won TEC awards, AES awards and the C1 was recently chosen as a BE Radio Hit Pick – out of thousands of choices.
I had $2000 sitting in the bank for a Neumann U87, Lawson or maybe a Gefell. $1777 of it is still in the bank. : )
I posted my review on 6/1 and have since had the mic for over 2 months and used it on many vocalists and for many applications – and I still stand by the comments I made, This is one of the most exciting purchases I have ever made. I am truly in the presence of a great, classic-sounding mic.