I'd say get your "M", and get to know it for at least a month or so. 100 loads ought to be enough to get a solid feel for any vape. Figure out what you do and don't like about it. Will it be enough for you as a portable? How do you like vapor flavor & production? Am sure you'll be figuring some of this out for yourself while discovering some of the wonders of vaping.
It may be you love it so much you'll want another VC - like an OMNI. You may find you want bigger hits and/or something for home you will plug in. You may decide you want heavier vapor on the go.
It's so easy to get excited about vaping or a particular vape, especially here on FC with so many great people, their suggestions and the great info all over. But, think it better for most of us to settle in a little, figure what we do/don't like, then move forward from there. Think we all do it the impulsive (wrong?) way some (know I do!), but is better in long run to find your vaping needs and desires and work from there.
Also, be aware that vaping usually becomes a very personal thing. On threads like this, you'll get many opinions - some that will probably align with yours, and some that don't. And, that you'll often get those opinions sometimes in the face of and contrary to facts.
Don't take me wrong - many great suggestions above!! But, a couple for instances - no offense to those who posted at all!
@steama (whose posts I always follow and pay close attention to) suggests VCs and adding a flower pot. Also selling off most of his other stuff and tempting me and others to no end!! (Thanks, steama!) I've been really tempted by flower pot because it looks awesome and that it does concentrates very well. You can even double load flowers and concentrates in same hit! I've looked at it a bunch of times and think I've determined while this is a great vape, it may not be best for me. There's a good bit of equipment purchase and set up, and think I'm better off sticking with some things I already have instead. However, if I was in a legal state, or had other solid access to trates, I'd be all over this one. If my vape area wasn't already so cluttered (or I wanted to get rid of, or put everything else away), I'd probably still be getting one.
Someone else above said DC vapes are more versatile than the nano, so better. In some ways they are. For instance there are many more types of stems available, and being DC native they're easy to power in a car. I've got a HI and a WS (which is most versatile IMO because of VC use with it), but my nano is still my fav of all because of the unmatched power and flavor of vapor - in part because stainless steel cup inside ensures you get absolutely no wood flavor in your vapor. Something I haven't been able to accomplish with the other two. And, plenty of versatility for me, even with only a few stem/GonG options. All 3 are great vapes I enjoy, and often really dig the slight wood flavor wafting in with the vapor. You may like it one way, or the other.
Anyway, back to my point.... Most prudent is to figure out what you definitely like, might like, definitely don't like, etc. The M should help with a lot of that. It's a great vape, and IMO the BEST entry level vape out now (cost, simplicity, portability and more!)! Once you get it, vape often and come on here and poke around while under the influence for more info on these vapes and many others than you'll know what to do with. But, as hard as it is, keep your powder dry (and your wallet growing) so you can have a better idea of what you want and key on things that you'll enjoy in a vape. And, don't forget they all usually go on sale at some point!
And, once you get all that figured out (or maybe before), be ready to do the same pondering about glass pieces, butane jet lighters, grinders, and the nearly inevitable VCAS (VapCap Acquisition Syndrome) that so many of us are afflicted with!
but I'm holding out until I've got a glass solution it will work well with. Also I need to define a vape station/desk for it all to work on. 
