The ship itself is very pleasant, airy and nicely decorated. The suite we had was nicely appointed and the service was broadly attentive.
The problem with Arvia is that it's the ship that likes to say no. Want to go to a show? No. Full. Quiz in the pub? No seats. Want to go to a restaurant? Sorry, should have booked last week. Kid's club? Forget it, slots in this Easter cruise went in a matter of seconds - it's your fault for daring to be off the ship on an excursion when the slots went up anyway. If you're a spreadsheet holiday planner maybe this works for you - it didn't work for us.
We did pick up some cancellations for kids club and it was reasonable (although things like 'make shaun the sheep' turned out to just be making a paper headband...)
B15*** is very nice and the staff were attentive. Plenty of space, nicely decorated and comfortable. The balcony was essentially useless because of high winds whenever the ship was moving, meaning that really it didn't get much use and the furniture spent most of the time tied up which was a shame. On the few occasions we were able to use it in port it was fine.