Sn0wBreeze is like PwnageTool for Windows. It allows you to create a custom firmware while preserving the baseband and hacktivating the phone, thus making it possible for you to unlock using UltraSn0w. But how reliable is Sn0wBreeze?
Historically, most people have had problems at some point using Sn0wBreeze. While I have a huge respect for iH8Sn0w, I still wouldn’t recommend the use of his tool. If you don’t have a Mac and can’t use PwnageTool, I’m sure you can always find a friend or family member who can create a custom firmware for you.
At the end of the day, do what you think is best for you. If you do decide to jailbreak using Sn0wBreeze, I’d like to hear about your experience. I hope you can prove me wrong and show me that SnowBreeze is indeed a great jailbreak.