Hey there. Quite honestly the HR Block tax class is not bad at all. I actually fell into tax before I fell into the CPA , and from first hand experiene I want to lay out the difference between working at a CPA firm and working at block.
At Block you go through the class, which you have to pass at the end (my class had two out of 12 pass..I was one of the two ;. Not sure if this rate is standard, or if there are just a bunch of idiots in my area). You then pick a location and get to work. Your first year they will hold you back unless you are clearly able to excel (they tried to put me into management my first and only year) , but honestly most block returns are easy anyway, the tough stuff goes to the higher up offices. The most valuable experience I took from Block was interviewing skill. Because of their business style you basically have client after client after client, and interviewing becomes second nature. You dont get paid squat. And from my experience you end up in an atmosphere of older ladies who took the test ten years ago, and really havent updated their knowledge base since. (On a side note, and one that makes me smile...Blocks business is about to be entirely altered by the RTRP test which becomes a requirement here at the end of 2013. You cannot pay people 9-10$ an hour and expect them to pass that test. They will either change business strategies and consolodate, or become much less competitive on a price level).
At a CPA firm you may be fakeing your experience for a while. I had a coworker or two who were excellent accountants, but didnt know squat about taxes, but felt the need to "pretend" their supperiority (probably because of the general level of expected excellence from a CPAs clientelle). At most CPA firms, you never see the client. You are given a stack of returns to complete, many of which will require contact with the clients, but just for pieces of necessary info. You will get paid more, and handle much more complicated returns, but you may end up understanding less in the end. Proseries is an awesome piece of software, and even a dummy who has no understanding of what they are inputing can become very good at simple input.
A happy medium may be to take the Block class, and then find a CPA firm that will take you. Id start trolling Craigslist and state CPA website for tax jobs around late October. Also, Block waives a non-compete in your face after the class, but from my understanding none of the info they give out is proprietory, and to this day there have only been cases thrown out in relation. And they probably wouldnt go after you unless you set up your own shop the next year. Last thing, and you are probably aware. Both Block and the CPA firm will probably only be hiring for the season.