Hirocoin claims to be GPU coin....
Hirocoin and Darkcoin use the X11 algorithm. X11 does not give GPUs a huge advantage over CPUs.
All these 11 hash functions have efficient circuit implementation as a design criterion.
So they're all very ASIC friendly, just like SHA256.
If the GPU implementation doesn't have a huge advantage over CPUs,
it can only be due to lack of proper optimization.
This is all the "X11 whitepaper" has to say about X11:
Darkcoin uses a new chained hashing algorithm approach, with many new scientific hashing algorithms for the proofofwork. X11 consists of blake, bmw, groestl, jh, keccak, skein, luffa, cubehash, shavite, simd, and echo.
Because it is more complicated than a SHA256 ASIC implementation,
the use of X11 will prevent the use of ASIC miners for the short-term to midterm future. It will also allow for a longer period of mining for CPU/GPU users.
GPU miners that mine with the X11 algorithm are currently experiencing reduced power usage (up to 50%) and reduced heat generation compared to scrypt.