Telephone

Please use the search at the top of this page - there are numerous discussions on the subject. For me:

I just add it to my Verizon plan for the $40/month and buy additional data as needed. It is easier, I have all of my info in my phone, if I need assistance I can talk with an English speaking person, if you buy a local sim customer service will be in the local language, I keep my phone number so it is not an international call if family needs to call me, I do not want to waste my vacation time buying a local phone/sim and trying to get assistance with it if there is a problem.

I just consider it part of the cost of the trip - this is by no means the cheapest method but it is the easiest.

All of your ideas can work. It depends on just what you want or need from your phone while in Europe.

If you're using the phone a lot and want to be able to use it without restriction when you're not in a WiFi zone, you'll want the local SIM card. Be aware that when you put in a local SIM you get a new local phone number, and can't access your US number. So, if people want or need to call you while you have the local SIM in the phone, they need to know how to make an international call or text - and they have to be willing to pay for it. Depending on their plan, it can be cheap or expensive to do this.

If you're just using it for emergencies or occasional calls, the Verizon plan is fine. It quickly gets expensive for more regular use.

Viber works if the person you are calling or texting also has Viber, and if you are on WiFi when you use it. If the other person has an iGadget as well, FaceTime is even easier than Viber - again, as long as you're on WiFi. If you have to use data, you'll quickly exhaust any allotment if you're on Verizon's travel plan.

I also have Verizon and always just get the $40 per month/per device plan. You get 100 minutes of talk (I never even come close!), 100 texts messages, and 100 MB of data. The data is the big one since you can quickly rack up hundreds of dollars in roaming charges without it. I find that if I just use data when I'm out and about for maps, looking up information, and reserving tickets, it's plenty. I always hook into wireless whenever I'm at a restaurant or where I'm staying for the purpose of checking email, Facebook, posting pics, or whatever other thing I want. This plan has always worked well for us on multiple, multi-month trips to Europe and other places abroad. It's much easier than messing with SIM cards, etc.
Also remember to keep your phone in airplane mode whenever you are finished using data.

gary,

Harold provided a good summery of your options. As stated your phones would need to be unlocked in order to use locally purchased SIM cards (I believe Verizon iPhones are unlocked, but you might want to confirm that with them).

One of the problems with using a SIM card purchased in one country when travelling around Europe, is that it may not always be easy to top it up once you've left the country of purchase.

If your phone is unlocked, you could also use a SIM from one of the travel phone firms such as iRoam, Cellular Abroad, Telestial, Mobal or Eurobuzz (there are others). These provide consistent rates through most countries in Europe, and often have post-paid billing (calls charged to a credit card), so no need to top up. The advantage of a travel SIM is that you'll have a working phone as soon as you step off the plane.

Rather than top off a SIM in another country, I use one up as much as possible in the country where I bought it then get another in the next country. That works better when the number of countries visited in your trip are few.

I do what Ken suggests and use a Sim card from a company called "One Sim," based in Estonia, I think.

I've used it on 3 different trips to Europe now. As long as I add a top up within 10 months, I don't lose my minutes.

On my first trip to Europe, I bought a couple of Orange sim cards through eBay and topped them up at Heathrow airport on my way to Paris on a trip to Paris and London. Our older teen kids had one phone and we had another, and we used them mainly to text each other when we chose to split up and do different things. That worked fine for us, also, and we did lend a card to a friend's daughter when she travelled, but once we were home, they expired.

I guess it depends on what your provider charges and whether you think this will be your only trip within the next few years.