I would agree with the prior two posts completely. I would also advise you to start asking around to see if anyone you know, might be looking for a CPA firm for various work deliverables (taxes, audits, tax planning). If you managed to secure a decent size client, the firm will be more hesitant to let you go at the end of tax season, since they will possibly need to part ways with that client as well.
I would say definitely take this position, but BE VERY WARY. I was offered 2 full time offers, the year before last. An accounting firm offered me a position while a company also offered me a position. The company offered a material amount of money more (think 10k-that's after me negotiating the firm up quite a bit, the accounting firm wanted to pay even less) than the firm and required fewer hours. I ended up choosing the accounting firm. Guess what happened?
After tax season, the firm ended up laying me off. I never received any warnings or anything; one fine day in May, I was told the “chemistry” just wasn't working. Then, BOOM, I no longer had a job. I heard that the same thing happened to the guy after me. Once tax season was over, he was gone as well. I don't want to be a downer either, but this practice is fairly common at smaller firms. I was told by someone else that at my old firm, we worked more hours than those at larger firms, while making less money and receiving less training.
These small firms are so dependent on tax revenue, that after tax season, things will die completely-they're very volatile. You'll be shocked at the change; it is at this point, when you need to be wary. The slowness is NOT a good thing, despite what it seems.
On an optimistic note, not all firms do this; I just wanted to point out that it's an extremely common occurrence. Overall, it's possible this position could work out, just be wary (especially with the “probationary clause-” all states are different, but this might be a strategy to avoid paying unemployment benefits in your state).
B=84 This exam was such a b**** that I thought I failed-don't know how these things work
A=76 Slacker I am, I'll happily take it
R=81 I LOVE taxes
F=80 I don't wanna get banned for an expletive I'm thinking with "yea" proceeding it