Ok, I'm still relatively new to this, too, so I'll try to give you some advice from my perspective.
I started with the M401. Ordered a starter kit (2 batteries, 1 atomizer, charger, manual that was written in English, translated to Chinese, then re-translated to English again), then ordered 1 spare battery and 2 spare atomizers. Had enough parts to make three complete e-cigarettes. About a week later it arrived, spent the next day fully charging the batteries, which was fine because my juice didn't arrive until two days after the kit arrived. With the M401, I never looked back. It wasn't 'exactly' like smoking a cigarette, but it was close enough that I never really wanted to smoke another analog after that. To this day, the M401 still has a place in my usage, when I'm on the go.
However, about 10 days in, I became really curious about how the other devices compared. So I ordered an DSE801(pen) kit and a DSE601(pipe) kit. Now, my primary device is the DSE801. Hands down, it has the best vapor:flavor:throat hit balance of all my devices. Plus, as a programmer, having the USB passthru is a necessity, so I rarely use batteries on the device. And, as an added benefit, the lack of the 'cigarette' feel has really helped to remove myself from equating this to analog smoking, so I'm at the point that I really don't miss analogs any more.
The pipe is a unique beast for me. Tons and tons of vapor, but very little throat hit for me. I use it as a relaxation device, mainly. I get very good flavor (more than the 801) out of it, so I use it when I'm sitting back and watching a movie, or (Nerd Alert!) playing D&D with the other guys here at the office, even sometimes when I'm driving.
All in all, I give the M401 a lot of credit for being a top performer and giving me what I needed to get past the initial break from analogs. But I have to admit that the DSE801 model has taken it's place as the top device I reach for after a month of vaping experience.
Ivisi
P.S. An even bigger difference in opinions is juice selection. I chose Johnson Creek as my first juice purchase, and I wish that I hadn't. The flavor, although good, was very weak. Having just quit smoking, my taste buds weren't exactly on top of their game, so I just wasn't getting anything out of the juice. It wasn't until I grabbed some LorAnn's from a bakery supply and mixed up some stronger flavorings that I really started fully enjoying it. Now that I'm a month in, I've gone back to that original Johnson Creek bottle, and the taste, although still weak, is much more noticeable than when I first quit.
