Other than items we can put on plastic, will we be better off converting to to EC$ or just using US?

(Taxis, gratutites, corner bars, local grocery, etc.)

we had NO problems using our $$ for tips and cab fares and purchasing souvenirs at stores...so we never converted.

We used US$ all the way. Put tours and hotel gift shop purchases and massages on credit. The gift shop actually had the prices in US$. There is really no need to exchange.

All places take US $. Do not bother getting EC.

Everyone takes US dollars so I would not worry about getting it changed altough when they give you change back some of the smaller places will give you change back in EC. So be prepared for that.
A good idea would be to take small US bills with you for tips etc. (most people will not have change for you- so try to have small bills when going on water taxi's etc)

Agree with everyone. The locals are thrilled to receive US$ however you will get some change back in EC$. ALSO, please note that there are NO ATM Machines, so bring any cash you intend to use. The only other option is cash advances from the hotel's front desk. Other than that, we put everything on our credit card because you get a better exchange rate than what the locals give you (US$1 = EC$2.60).