Any Speecheasy (or similar device) users here?

Any Speecheasy (or similar device) users here? I'm really interested in getting one but I can't yet justify the cost of it. I'm wondering if it's still effective in the long term, when used only a couple of times per month. I know that it's something that can't be used often, but I'm not really sure how often it could be used. Anyone have any insight on this?