I have used MDT6 with Power Pack and the AutoPOL sheet metal add-on. One thing you have going for you since you have used MDT is that you already understand working in 3D. You understand how constraints work in sketches and models.
A strike you have against you is you have used MDT, so you will get frustrated with SW because it doesn't work the same (which is a good thing). Parameters/global variables are very week in SW compared to MDT. You start using too many and the system starts slowing down. But you can use skeleton sketches in assemblies so you may not need variables as much.
File management is something to implement if you haven't already. Creating a naming convention is something else to consider because you will find yourself re-using parts and assemblies in SW.
Also, In MDT I worked top-down in assemblies, but in SW bottom-up.
If you have used MDT with AutoPOL, you will find that SW sheet metal isn't as strong, but considering sheet metal is included in SW, it isn't bad. SW cannot create sheet metal transitions, square-to-rounds, helix's (for spiral stairs) or other complex flat patterns.
Depending on the type of work you do and the complexity of it, you may find yourself running smoothly in about a month or so if you follow the tutorials in SW and leave MDT behind. After using SW for awhile, you will find MDT very "clunky" for lack of a better word.
SW06 SP5.0
Flores