Have been on Arvia, Iona's sister ship.
You can share WiFi but only one device can be logged on at a time and you cannot hotspot.
Food is amazing. We prefer to use the main dining room rather than buffet, but love The Quays on shore days for breakfast and for late lunch once back on board. Do use the 'app' to get in the virtual queue for MDR; it shows how many are ahead so you can have a drink or whatever rather than standing in the line.
The medical centre is incredibly well equipped but you do have to pay to visit. I think I paid £80, but it's more expensive overnight.
Join the Facebook groups, a wealth of information from experienced cruisers.
Check the rules for taking alcohol onboard, I think you can take a litre of wine per person for consumption in the room. We took a (decent) wine box for ease which fit in the fridge. And soft drinks are unlimited. Take snacks for the room if you like crisps/nuts as those are £££ in the gift shop.
Other things we take:
Laundry detergent sheets
Large net bags for the laundry just in case someone decides to empty your machine
A small bag for onboard, for cruise card, hand sanitiser etc.
There will be a formal night but no need to go over the top. The menu is slightly elevated in the MDR, so we usually book Epicurean for another night. And check who is on at the Limelight, that can be a good evening.
The live music is really good generally and my favourite is the 710 Club but you have to be quick to book it (it's free but very small venue).