Pros
The experience you receive from working at an H&R Block office really depends on its location. Some offices have around 10-15 employees, which makes it difficult to really get an hours. I was lucky enough to work in an office where there was about four other employees, including the manager so there was plenty of hours to go around making it a full time job for me. Co-workers are great to be around and everyone helps each other out.
Cons
Unfortunately, unless your just looking to get experience in preparing taxes, working as a Tax Associate for H&R Block is not what it's set out to be. The office positions are all seasonal so you work from the beginning of January to the last day of the tax season (3 1/2 months). They tend to keep some of their EA's and CPA's during the rest of the year to handle any audits or year round support, but again, the pay isn't enough to sustain living expenses, so you would definitely need another job while working for H&R Block. Another thing is that they make you market the hell out of H&R Block. It does't matter whether it's your first year or your 10th year working for H&R Block. They make you market! Now, if you have a lot of clients you can simply refuse to market and essentially work off of commissions, which would make more sense than going to the office and waiting for clients to walk in and getting paid hourly. There are quite a few employees that do this, but it's their reputation that gives them the ability to do so. Biggest Con is they pay. H&R Block expects you to prepare taxes (taking on all the liability), market, and act as the person who sits at the front desk when there no one there all on minimum wage. This job is a handful for very little pay.