i'm not asking in a boating context or i'd post this in the other forum, where the smart people are.

so was thinking about getting one of these for cycling and wondered if they are worth the cash. by that i mean do they really work and are they easy to use. also, i was thinking of going with the cheapest but 5-star rated on REI as i'm not sure dropping twice as much is a good thing.

any thoughts would be appreciated. thanks