It has 90 base power, 100% accuracy and a 10% chance to freeze.
Ice beam with STAB results in 135 damage.
Has 60 base power and 90% accuracy. Always results in a critical hit.
With STAB and the critical hit it results in 180 damage in any generation before 6 and 135 in generation 6.
The answer here is pretty obvious.
If this is for Generation 6, Ice beam is better as it has the same damage, better accuracy and an additional effect(though unlikely).
If it's for any generation before however, you just have to decide what you prefer, more accuracy and a very small freeze chance or more power and less accuracy.
Source: some calcs and knowledge
Hope I helped.