Do you find a computer-assisted qualitative data analysis tool useful? I do a lot of qualitative coding and assessment as part of my research activities. Usually my colleagues and I simply use generic tools for this process like text editors and spreadsheets, but I know that there's a lot of software out there (NVivo, Atlas.ti, etc.) that is designed for making qualitative data analysis "better".

If these pieces of software were inexpensive, I'd probably buy a package and try it out, but they're very costly (about $600 per seat) and appear rather intimidating.

Can anyone with experience in qualitative data analysis comment on whether these tools are useful (or not useful) and are worth the high price? (And you get a cookie if you can describe a use case that really highlights why the tool is powerful!)
My answer might not be as useful to you because it only deals with my personal experience. I often deal with mixed methods work and qualitative data analysis is something I do about ~25% of my time.

I have used Atlas.ti because it is provided free on my school server. However, realistically, I used Excel to code themes, categories etc. following a grounded theory approach (Glaser and Strauss, 1967). I don't find much use for it but I know significant numbers of professors and graduate students who swear by it. It seems to be the SPSS of the qualitative world.

One powerful use of Atlas.ti that I can attest to is organization, search and visualization of categories, codes, themes and performing some simple reliability measures (Cronbach, Krippendorf) etc. 

However, the same can also be done in Excel with some elbow grease. :)