I have the only cuda miner in existance. (rpcminer)
It seems that because the cuda cards aren't as efficient at hashing, the community has altogether abandoned cuda and any new miner support for nvidia and cuda cards.

Even if someone dares mention the evil "nvidia" they will get 5 hashes at the mast.  
The RPC miner defaults to 4000ms polling.

So this means that there are a ton of nvidia users out there with outdated miners (because they have been abandoned)
Unless they all use the switch -workrefreshms=100 their polling rates will stay at 4000ms.

Don't tell me to get ati cards, if I had that kind of money, id just design my own fpga/asic pcb and be done with it.
I use what I have.   Now if someone is willing to throw me bitcoins so I can buy two of the latest ati cards..go ahead, my address is in my sig.  
But then id need to purchase a gpu mod for my swifttech gpu cooler blocks.   And I'd have to re-run all my PEX coolant lines...etc...

I'd rather just use all the money and extra effort, by doing a fpga/asic design. (i used to do dsp/fpga design for milling machine controllers and drives)
 Why buy new vid cards if they are going to be as useless as nvidia in about a month or so.