Finnish Lapland got a hold of Santa Clause and have been using him as a cash cow ever since.
Almost anywhere is commercial and somewhat gimmicky, and it is all pretty much the same anywhere.
Rovaniemi is the larges town(city) in Finnish Lapland and thus has more to offer, but it is not as scenic and beautiful as many other places.
Kittila/Levi does not look very Finnish when you get there, i got the immediate feeling that i was in a Alp town not in Lapland. But the scenery and are is beautiful.
If you want smaller towns and more personal, go to Saariselka, Akaslompolo or Salla...or if feeling adventurous go even further north.
But be aware that you will have much less choices in the smaller towns/areas(Saariselka for instance has only one store and if you plan on self catering you might want to figure out a way to shop elsewhere before going there) all have several restaurants tho so it is easier if you plan on eating out.
Also, the bigger safari companies that are primarily in Rovaniemi(but do also operate in some of the other towns) are more "wholesale tourism" and you will often not the real authentic Lapland feel from their trips. But all do try and cater for anyone, just expect to have to pay extra if you don't want to be stuck into a group of other people.
5 nights should be a nice trip.
Also keep in mind that if you do take the car hire option and want to go from one place to another that it is dark for most of the day and all of the night and that heavy snow and ice conditions are normal...so if you have no experience with such driving be prepared for a shock(and getting stuck or worse!) also remember that distances are long here in Lapland.