I've tried out all the mapping software. I don't think any of it works for these games.
The modern D&D software programs are too concerned with tiles and set pieces and typically don't let you accurately represent the dungeon space of an old school dungeon crawler. How do you show darkness, mana drain, or spinners?
The same sort of problem afflicts these nice specizalized apps.
For example the Dungeon Crawl mapper without bullshit is neat, for what it is, but how are you going to to write down "this is where the dragon is" ? or "these 20 squares are health point drain for male chracters".
Basically the specialized apps all fail to handle any but the simplest dungeon crawlers. This one at least lets you handle block-walls, and thin walls, and stairs-on-edges as well as stairs-on-squares. But it won't be good enough for M&M or Bard's Tale, etc. For example, is there an easy way for you to mark squares you've visited vs squares you haven't? You want to mark them in the positive (you've been there) because marking them in the negative is error prone and tedious.
I mapped out Phantasy Star using this nice java app (similar to the no-bullshit mapper) http://www.zerker.ca/zzone/2010/01/10/dungeon-mapper-0-1-alpha
/ but when I made a mistake it was very painful to fix, having to just do everything all over instead of like.. undo or copy the stuff one square to the right.
In the end I went back to using Inkscape with a snap-to-grid and some specialized symbols I cooked up as I needed them. It's easy to make symbols. Just draw some conceptual thing in large scale, then zoom it to the right size and make it an object you can copy and paste as needed. Your legend doubles as your palette. The downside, as always, is it's slower than paper. Also you may have to put in some initial time to learn the basic inkscape controls (or excel or whatever you chose). It's not that hard though, all you have to learn is item selection, node selection, and some keystrokes to swap between stuff like select, nodeselect, text entry, and linedraw (s, n, t, and b for bezier). Managing the depth of items within your layer can be an issue but it's a simple concept and the menus will work for how often you need to do it (very rarely).
The other major choice is Excel with the "draw border" feature on the cells which is very time-efficient, but makes representing odd things like one-way-doors very challenging. I think this would work OK for a simpler crawler but for the more challenging it may be hard to track things like a one-way secret doors or elaborate teleport-trap mazes. (actual arrows pointing from origin to destination across the map can be so nice here).
If you like I can upload my copy of Sorpigal for you to run with, though the legend is mostly not labelled because it's leftover symbols from bard's tale 3 and I don't know what will be useful yet.