Hypo would be my choice. I just got done doing on my tiny yellow clown goby. It's really not that big of a deal to the fish... in fact, the lower salinity decreases the stress on it from regulating its internal salinity to the external salinity, and allows it to devote more energy to getting better. In addition, the lower salinity kills off the ich parasite. Except for a lack of coloration for a couple days, the goby couldn't seem happier in SG
1.009 for 5 weeks!
The "kinder gentler" copper-free medications, in my opinion, are just snake oil... they don't do anything to rid yourself of the ich. At best, they just interfere with the life cycle of the parasite, but they don't rid you of it. The copper-free/reef-safe products are around because they play on people's need for a quick fix that doesn't require taking the fish out of the main tank, and the fact that ich "comes and goes" as part of it's natural life cycle. People will use the stuff, see the ich go away, and say "Oh... it worked! Hurray!" And then the ich will come back. Folks will then say "Oh... I guess I didn't use it long enough", and start down the same road again. But the fact is that even if they used nothing, ich will appear to go away after a few days, only to reappear after 7-10 days, but this time even worse.
Obviously I don't have any experience with the copper-free ich medications, but figured I'd chime in with my nickel's worth of advice. Perhaps someone else here has had first hand experience with the stuff.
[Edit: Here's a good article on hypo... http://www.petsforum.com/personal/tr...osalinity.html