When you need to fix a map right then and there you can do it..
The only major setback I find tho is that it just does textures so if you need to make a map you gotta make it blank first then work off that which can be a bit tedious.
All in all tho it does what it says it does and it is a must have for all mappers.
Visual Mode is a plugin that allows you to texture maps in Aleph One. It supports almost all features of Forge's visual mode, plus OpenGL, multiple texture sets, and more. Requires Aleph One 1.7.