I own the helix syn, eupho syn, helix syn v, and the mgx syn.

First, I do NOT like the P-tab. That will be my biggest criticism of this model, and most of the other similarly 'tabbed' models as well. I will submit feedback on why and how I think it could be improved, but it's a lot of detail and not necessary to go into all of it here...

There are several things I like about this model, however. The shape of the base is curved in a (concave?) manner that is different than most of the other models, and causes it to be seated a little bit better. Also, the bottom of the stem is tapered and that too helps the massager be pleasantly seated, unlike several of the other models that feature a small bulge at the bottom of the stem (I don't know what that's for because in my experience it just tends to make the device slip out further than it should).

As far as fitment goes, this is the best of any of the models I have tried so far. That being said, the stimulation is pretty strong because and I've found it at times to be almost a little too much. The benefit is that you don't have to flex as much and because of this, subtler movements can be felt more strongly.

I like the shape of the head, and I like that it's got a prominent almost pointy shape to it, while still having a decent width but I wouldn't say it's too much. This aids in stimulation similarly to the eupho model but the mgx is a little more direct I'd say.

I'm kind of torn about the ridges at the base of the stem. At times, I've found them to be pleasurable but I think mostly they are just distracting to me. I think a smooth model that is shaped in the same way would be really good.

Lastly, it's blue. Cool detail, good cause. Kind of neat to have one that's different than the rest.

I like how flexible the tabs are more than the helix and euphoro syn. The ribbing at the base gives me crazy anal sensations I haven't had before. It would be nice if there was a larger model with the ribs in the future.

I have had my Aneros MGXSYN for about 2 months. For the first two weeks, I spent most of my time figuring out the logistics and procedures for my sessions. I did a lot of reading of the WiKi articles as well as the blogs. There is a wealth of information there, and it helps to re-read many of the articles for things you missed. During those two weeks I figured out how to prep - I use a bidet to clean, how to arrange a towel on the bed, what kind of lube to use - I tried 4 different ones before settling on a water based gel type. I also played with various music and ASMR (?) music - Mindgasm. During those 2 weeks, I had some minor successes - twitching, muscle spasms, tingling feeling in penis.
I then started listening to the Mindgasm lessons. That was really the key for me. During the first lesson I had many HFDOs and good feelings. The combination of flexing and toning different pelvic muscles was the factor that sent me into many involuntaries and good feelings.
At about week 4, I started including some nipple stimulation - caressing around the nipples and then flicking them with fingers. Every time, this resulted in the muscle spasms and vibrations associated with HFDOs. I happened at one time to come to a period of “idling” - just a slow, rhythmic, torso wave of movement. This went on for several minutes and was very enjoyable.
My wife is supportive of my efforts to take care of myself and was interested in how I did a massage session. I showed her what I did and she was very inquisitive and trying to understand how she can support me in my endeavors.
My current session consists of setting my watch for a 10 minute timer. I turn on the “Launch” session of Mindgasm or some other music and use the MGX as a stimulator to my my body. I let it dangle between my fingers and gently bounce it against my balls, perineum, nipples and torso. This excites my penis and I get hard. After about 2 or 3 minutes I put some lube on my fingers and touch my anus and inside. Then I lube up the MGX and gently insert it. I am usually laying on my back with feet flat on the bed, knees up. For the balance of the 10 minutes, I just relax, listen to the music and do not consciously try to do any contractions or twitches. Almost immediately I begin to have spasms and twitching involuntaries. When the timer vibrates, I reset for 30 or 40 minutes depending on the time available. This passes quickly with almost continuous spasms and bucking. I refrain from touching my penis and enjoy the feel of it slapping against my thigh or belly. At the end or the session I again set the timer for 10 minutes and try to wind down by relaxing and breathing, but this rarely happens!
I consider myself lucky to have this response and success so quickly. I look forward to many more sessions of learning and experimenting. I think the p waves have still eluded my sense that I am having them although my face and upper body does get flushed and I feel terrific for several hours after a session.

Blue MGX Syn Trident