I just never seem to get around to getting a travellers card, and I can't be bothered organising one for this upcoming trip since we're only away 2 weeks and most big expenses are paid. But I can definitely see their benefits. Particularly if you are committed and start loading them about 6 months or so out - every time you notice a strong dollar.
At present I just travel with cash and credit. I get enough cash that I am well covered for small purchases, tipping, or any situation where I can't use my cc or don't feel comfortable doing so. For the USA in particular I go into the back and put in a money order for US dollars. The bank usually carries twenties and fifties, but I always want at least $50 to be made up of smaller notes such as fives and ones. That way I'm ready straight away to tip shuttle drivers and baggage handlers etc.
All bigger purchases I charge to my credit card. As long as I don't make any cash advances, the fees are no different than when I use my CC here in NZ to pay for overseas hotels, car rental etc. It's a fee I'm okay with and I get roughly half of it back anyway in reward dollars. I then just make sure I pay everything off before the interest kicks in a few months later.
Also worth noting, when I compare the exchange rate set by my cc to the exchange rate set by the travellers cards I can choose from here in NZ, my cc is almost always stronger. I did the maths once, and I noticed that even though my cc charges a small overseas transaction fee, and the travellers card I was looking at didn't, the better exchange rate and the reward points I was getting for my cc made up for this. My advice when it comes to comparing all types of cards is to not just look at the fees, but also at how they calculate their exchange rate.