I've been a STH for five years and honestly, it is a bit of a mixed bag. The April games are always going to be a hard sell and the past few years, the last six weeks of the season are difficult to sell too. Weekend games from mid-May until August usually sell, and the summer night games will too. But there are so many tickets available on StubHub that there are very few games for which you will get full face value. Plus StubHub takes 15% too.
A big part of it is location too...our first year, the seats were pretty far down the line and they didn't sell very well. We've moved up each year and we are in the first row of the upper deck just behind 3B. These sell much better than in past years.
When we got on the waiting list, we had eight people who said they were in. Seven years later when we got called, we only had four. We lost two more before last season, but added one new guy this season. Your best bet is to find some people to split the pain with or find an existing group to join.
Sorry if this makes it sound scary! We have lost money each year, but we look at it as an investment that will pay off when the team is good again.
Let us know what you decide...