Well if they work that good it's easily worth it. At certain hours Decaptcher is unusable 100% server-load constantly.I am using bypasscaptcha. They seem to be the most expensive $14/2k but rarely get one wrong and seem to ALWAYS have capacity.
For under 1 cent a call - I am very pleased with them but you are paying a premium over the others.
Edit: n/m they are no more expensive than the other 2 listed above.