Hello Darin,
I was diagnosed about a year ago with a 2.5 cm AN, similar symptoms except for some reason no tinnitus. Wanted to pass along a link to my website, where I recount in detail the process I went through in terms of researching treatment alternatives (see my sig line below). Ultimately, I selected CK but surgery is a reasonable option, with its own attendant risks. It sounds like you are well on your way to making a decision, but I thought the site might be helpful as you weigh alternatives.
I had similar kind of balance episodes before treatment and as you will see in the "post-treatment" section of my site, the unsteadiness has continued intermittently after treatment. My doctors tell me these balance issues usually subside, usually within 18 months of treatment, so we will see. I am pretty confident they will. In any event, some doctors will recommend taking certain balance tests before treatment to determine how the tumor is impinging on the balance nerve. I would follow through with those types of tests and learn what you can about how the various treatments will impact your balance symptoms.
Unfortunately, I feel the data out there about post-treatment symptoms is just not that great. The ANA conducted a symptom survey in 2007 but they still have not published the results. Maybe they will give you a glimpse if you contact them. They did a prior survey in 1997 or 1998, the results of which are on sale at their website (go to the On Sale section). Definitely worth checking out. Surgeons will likely say you will have intense dizziness for a few days or weeks after surgery but that will fade away fairly quickly as your body adapts. This is true as far as it goes, but I do not know if it paints a complete picture. I think both radiation and surgery patients have longer-term balance issues, but it is hard to tell the extent to which that is the case. Again, I think the surveys and quality of life studies are the best we have to go on right now.
There are links on my website (in the "choosing a treatment" section) to medical abstracts summarizing the results of quality of life studies comparing radiotherapy and surgical outcomes. Also worth considering and asking your doctors about, I think.
Best of luck to you. Please let us know if there's any way we can help.
Francesco