The C01 was the first recording mic i ever bought and was a step up from using dynamics to record but it's kind of harsh and metallic at the top end. I own a V67G now and it's much nicer sounding. I've never used a SP B1 but a lot of people seem to own and like them here.
Like I said I've not used the SP B1 but if you use the search function you'll find lots and lots of threads with people saying good things about it (I'm pretty sure you won't find any positive ones about the Samson!). I know I'd go for the B1.
I actually bought my MXLs (I have a pair of 603's too) from a guy off ebay in the US. Even with shipping and import tax (at 17.5%) the mics cost more than half what I would have paid for them here in the UK. So maybe that's something to consider?