I don't know about the others, but Tasm has one really cool feature..... It supports Object Oriented programming in assembly... Using some complex declarations, you can do pretty much everything which is needed in OO: classes, inheritance... Funny thing, but i do not advise to use it, except if you need to interface with OOP language...

The useful part however is that it lets you write a single method from your class in assembly, so that you can get top performance without sacrificing your nice OO design...