Hi Scott,

Metropol Spa Hotel is the best in terms of location, comfort and value for money.

There is also Hotel Viru, across the road from Viru Gate entrance.

I've stayed in both, but would recommend the former (brown building). I find it more convenient. There's also Metropol Hotel (green building) right next to it, as an alternative option.

There are also a lot of apartments and hostels in the Rottermani area. One is even called Rottermani Apartments.

Besides, if you are staying for a month, and a visit to Helsinki is part of your plan, you can consider Tallink hotels. It's one of the ferry operators and offers package deals in any of its properties.