I'm going to Switzerland next week.

Their local SIMs provide "unlimited" data for 2 or 2.50 CHF per day.

If you have an unlocked device and you want way more data and speed than the free international roaming plan, you pretty much have to look at local SIMs.

If I'm going to a country for more than a couple of days, I usually get a local SIM for my iPad, while using the T-Mobile in my iPhone. Or I will tether the iPhone to the iPad for faster speeds.

You can often get enough data that you can use as an alternative to hotel wifi, which will always be slower than LTE and even 3G in many cases.