My thoughts:
I've never used Tedds. Not sure if I've ever really seen it either. So, I don't know how it compares. My impression is that it's like a cross between MathCAD and EnerCalc. Though I'm not sure how that's possible.
The last company I worked for did a great job with Excel spreadsheets. Look up tables and drop down lists and such. All their commonly done calcs were in Excel. It was really cool. But, seemed like it would be a pain to set up.
I used to use MathCAD a lot personally. This was never to submit to plan check, but to verify / validate other programs or calculations. I both loved and hated it. Loved the ease of use and how I could write up a MathCAD spreadsheet to look just like it would if I were doing a hand calc, but without the mathematical errors. Hated the company itself. They were constantly changing their file format and licensing stuff to try to bleed more money out of their customers... at least that's the way I interpreted it.
I've used Enercalc off and on over the years when working on side projects with friends. I like it, but don't love it. It's got a lot of what I need to put together simple calculations that can be submitted to plan check. And, I felt like the price was reasonable. But, it just never felt like there was any "wow" factor. Meaning, I always thought that if I had the time, I could do it better.
I personally think RISACalc is a bad joke. I just don't see how this would be useful to anyone at all. It seems to be just a stripped down version of RISA's other projects. Granted, I've never used it so what do I know.
Caveat: I used to work for RISA and I currently work for CSI (who makes ETABS and SAP2000), so I'm not exactly an unbiased observer on structural software issues. RISACalc was under development when I was there, but I never really understood why management thought it would be a good thing. Maybe they were trying to take market share away from Enercalc? Perhaps with the hopes that those "small time users" would eventually upgrade to RISA-3D or RISAFloor or such. Seemed like faulty reasoning to me....