Hi,
VHO
1. have fuller spectrum of light
2. bulbs have short life, I bellieve only
6 months to a year.
3. get hot
4. are fairly expensive to run
PC
1. initial setup cost is significantly
more
2. bulbs produce much more intense
light ( in terms of lumens )- but not as diverse of spectrum
3. Bulbs have very long life, upto 16
months in some cases
4 heat due to lights is not much of an
issue
5. when using electronic ballast, cost
to run is nominal comparitively
having said that, I use pc lights but most use VHO... you can even do both! The decision is still yours, what size tank do you have?
HTH
Josh