Edit: OH, I see DSoL was faster than I am. I hope this isn't too repetitive of what she said.
Hey and welcome here!
before I can help you, I think I need to know a little more of what you want to do.
You say you are not only going to see POTF, so I assume you are planning a vacation in Europe? If so, is there a specific time you want/need to go there (for example it has to be sumer, because you can't get vacation any other time or in the winter, because skiing in Switzerland is also on your to do list)? Or can you plan your trip around a POTF concert?
If you are free to plan anything, the next question is for me is about your budget. I don't know about Canada, but from Germany flights to Finland are a lot more expensive in summer. Also it is easier to find an affordable hotel when it's not the main season (June, July, August).
If that is not an issue the basic question is: club gig or festival. With a festival you will get many other bands, but the tickets will be more expensive (between 40 and 80 € depending on where) and POTF will likely only play 45 minutes, at least in Finland. A club gig is more intimate, usually about 90 minutes long and cheaper (15 - 25 €), but usually starts later (anything before midnight can be considered early) and might sell out fast (at least in Helsinki or Tampere). That being said, festivals are in summer, club gigs in spring or fall - usually anyway.
The tricky part is that gigs sometimes get confirmed rather late. This year the spring gigs were announced early (i.e. in November/December), but for some summer gigs it was less than a months before the concert. It is sometimes difficult to get confirmation from all parties. So if you want to do some long term planning, you'll have to hope that something is announced early on. Word of warning: If a venue announces a gig, even if they sell tickets, it does not mean the concert will happen. Only if you find the date either on Live Nation's site or on POTF's official site it is confirmed. As of now, there is no telling what will happen in the fall or next year. There will be concerts for sure, but the when and where nobody knows yet. Currently, the summer our is being planned and announced.
Best shows? Well, that depends really. I have seen great shows at festivals and in clubs, in Helsinki as well as remote parts of Finland and in other countries too. Helsinki has an easy crowd (meaning they are appreciative of the band and the band does not have to work hard to get them into the show), but there's no guarantee that shows there will be the best. The advantage is, that Helsinki is easily accessible via plane. This also means that many foreigners come to the shows there. Finland has good public transport, so as long as a gig is in a big city, you can easily get there by train or bus (or plane).
Outside Finland I have seen amazing shows in Russia, Ukraine, Germany and Estonia. For Russia you'll need a visa and it's hard to get tickets from outside the country, so unless you have Russian friends to help you, it might be difficult. Also the gigs there always seem to be in winter. The other countries are easier, but there is no guarantee for concerts there. The Poets do not regularly play gigs anywhere but Finland and Russia. The advantage of concerts outside Finland is that you will understand what is being said on stage. In Finland, they will speak Finnish and unless you understand the language, you can only guess.
I have to add that there is no such thing as a bad Poets of the Fall concert. They are all great. Some, however, are amazing, magical and there is no telling in advance which it will be. It all depends on the mood, the audience, the spark that either is there or isn't. It also depends on how you personally feel that day and what you like. The one thing that is guaranteed though is that their concerts are highly addictive and whichever one you see it will be unforgettable.
So there, this is all I can tell you for now. If you have any questions, feel free to ask. (PM is fine too)