by iced I suppose you mean "on the rocks" type of drink? We use syrup as well...Davenci's (sp) which are among the cheapest but they seem to be likable by our customers....I would use Gharidelli syrups if the quality was an issue for my customers but it doesn't seem to be.
We use powder for our hot drinks, but I'd never get that powder stirred into a cold one unless I blended it.
Also does your favorite use a hot shot, blend with the powder then chill on ice or?
And finally we use powder products for all our "frap" like drinks....