I am a "one man show" and the first thing I did when I set up business last year was get the Toolkit. I mostly use RSLogix500, RSLogix5, PanelBuilder32, RSViewStudio for ME, and occasionally other program such as RSNetworx for DeviceNet and RSView32. If I were to buy all these software programs and then keep the support up on them it would cost me a fortune. With the Toolkit I get all those products and a lot more.
I was awarded a CompactLogix project last fall; no problem RSLogix5000 is also part of the package. I think its an excellent program and I wouldn't consider getting my AB software any other way. Of course as someone else mentioned, its all about cost and benefit. If you only use one of two software packages it may be more economical to purchase them seperately.