Assioma Duos here. Not much else to say than what has already been said. They have been flawless (except when I forgot to charge them once 
) and I had no issues adjusting the cleat tension so they are comparable to my former SPD-SL cleats. Also did a video on them here:
I’ll add this: one reason I chose the Vectors over the Assioma was that I don’t trust rechargable batteries over the long haul as much as replaceable batteries. Could be dumb, but I’ve had issues with most electronics that are rechargable after a couple of years. Obviously you can leave them unplugged and help mitigate that, but I’m hoping the Vectors last me 5+ years given power meters are expensive (I got about 9 years out of my old PowerTap hub). Anyway, that was one reason I didn’t go with the Assiomas personally, but they seem great.
This was a possible concern of mine as well, but the charge lasts so long you can probably re-charge them at the same frequency as changing batteries with the Vectors (not sure of the real world numbers for either though). Both my Garmin 935 and the Assiomas have pleasantly surprised me with their battery life and I forget when I last charged them between charges (the 935 is more on the order of weeks vs. months with the Assiomas). knock on wood that they stay that way of course 
.
Another vote for the Assioma here. Plug and play, and I don’t give them a second thought. You can even upgrade later to the DUO once the budget allows. I’m not sure the Vectors allow for that.
I have Assioma and it works fine. I was having problems clipping in and out and solved it by adjusting the tension screw on the pedal. Now no problems.
From what I’ve read, Garmin has resolved the problems with the V3s. FWIW, I would have bought the V3s, but in April, they were in the depths of the battery door issues and back ordered indefinitely.
If you live in the US, the Garmins may be easier to repair. I fell and damaged the right pedal body on my Assiomas. Getting a replacement required ordering from Europe, with the attendant shipping time and cost. Favero only ships to the US by FedEx, which adds 30% to the cost of the pedal body, so buy from a 3rd party and save 1/3 of the shipping cost. If you live in Europe, the opposite may be true.
While it’s great to here they’re both good products, it doesn’t help me choose between them. Although the replaceable batteries has me leaning towards the Garmin’s whike my weight has me in the Assioma camp.
You’re probably probably not going wrong with either one now. If you’re in the US, as someone else said, you might consider the support by Garmin being “local”.
Assioma seems to have much better reviews.
No I’m in Australia but Garmin seem pretty good here too. Only problem is I’m 9 kilos over the weight limit. Frankly they’re kilos I could easily do without so the Vectors give me an incentive to lose them.
I can vouch for the vector 3’s myself, I’ve owned them all summer now - from what it sounds like you wont be disappointed with either!
Favero here. I had a bit of an issue with clip-in/clip-out tension, and you’ll probably hate the cleats that come with them (buy your own) - but otherwise, these are great. Light-weight, stupid easy to install, great battery life. We’ve already gotten some firmware updates, and I’d imagine ANT+ Cycling Dynamics won’t be far behind. For the price, these are great. I haven’t used any other pedal-based power meters, so can’t compare to anything else, but I’m happy with my Duo, especially for the price.
I hate the cleats that came with the Assiomas. Did you go to regular KEO cleats or something else??? Its not so big of a deal on the trainer, but on the road the tension is way to high for me.
Yes, the cleats that came with the Assiomas were awful, I got a pair of Look KEO 4.5% cleats that work fine.
I (and many others) have had issues initially with the clip-in/clip-out tension. Support sends out a Youtube link with a ‘hack’ that apparently has worked for some users:
I’d guess many of the negative reviews for Garmin were due to roll out issues - back orders, battery cover issues leading to connectivity problems and power spikes, calibration issues. Those seem to have all been resolved. Since getting my new battery covers, I’ve had zero problems with my Vectors indoors or out. But they really screwed up at roll out…
I currently have the Garmin Vectors the first generation then upgraded to the second. From the beginning it was the pods that came defective and had to warranty replace them. From there the only constant issue is battery and battery life. I could not ride for a week and then my Vectors start to acting up. One of the pedals drains in battery life and I would have to replace the batteries or be left without power. Its annoying. I do not know if Im the only one but sometimes when my MAC is connected to my speakers and the wahoo bolt on plus the TR app in my phone the Vectors go crazy on and off from the app. I have been researching the Assiomas for months, reading reviews and they look too good to be true. They will be my next purchase. I already sold my Garmin computer.
I went for Vector 3 on the basis of Garmin’s good customer experience. I did RMA mine and the process was quick and painless. No issues.
I would say that swapping the pedals between bikes isn’t as smooth or issue free as I might have expected. I didn’t appreciate how much torque you have to apply to tighten them; it takes a bit of effort to remove and install them.
I’d have no hesitation in recommending the Garmin Vector 3.
I’ve had Assioma Duos for about a year. I find the pedals spin a little more freely than standard shimano non-power meter pedals, so clipping is still a little more hit and miss for me than I’d like (though that could just be my technique). The other thing is I’ve had about 3 instances in the past year where one of the pedals went flat while the other still had >50%. Not sure why that happened and am dealing with support on it now. Otherwise quite happy with them.
Been watching this thread as im looking to get a pair of power based pedals for the ability to swap between bikes if i want. Not too often. Gravel bike now and switch over to TT bike and leave there in spring. So not swapping them constantly.
I have a quarq dzero on my main steed.
My question is Does anyone with either of these pedal based meters have the single sided? Do you have any regrets not having dual sided?
I can and do monitor my L/R ratio on my quarq,
Is there any other benefit from having dual reading pedals?
IF there is a small percent accuracy discrepancy is it noticeable do you think?
I don’t regret only getting the Assioma Uno (single sided) although I have seen my L/R ratio is 50/50 to 51/49 during a bike fit. I have no intention on getting a dual sided in the future currently. Only reason I’ve heard that might sway me is if I were to have an injury making the split larger.
Per the Assioma site, they have analytics as well, and their support confirmed that it has a lot of the same data across ANT+. Bluetooth is more limited.