I have not worn all the shoes but was in a similar situation to you where the super shoes just aren’t sitting in shoe shores waiting for people to come in and try them on. We have both a Nike outlet store and an Asics Outlet store 10 minutes from where I live so I checked there as well as the local running shoes stores and had no luck on any super shoe being available to try on. So I had to take a change and just order a pair.
I have been a loyal Asics runner since I got shin splints from a pair of Nike Pegasus 25 years ago. So I though the Metaspeed Sky might be the best shoe for me but with no one doing a start-up business to test people in the various super shoes to verify which one was right for them it was really just a crap shoot. I had found a few different studies on them and had seen reviews and picks from people who had run in all three. Most of the reviews said they were all good and you couldn’t go wrong so I just shopped for the best deals. I ordered a pair of Vaporfly Next% but they got lost in the mail and the next deal that came around was for Alphaflys to that is what I ended up with. My first run in them was about 6 weeks ago. It was a 13 mile marathon race pace run. 9 Miles into the run I was 15 seconds a mile ahead of my goals pace and felt that I could defiantly hold that pace for 26 miles. Then something weird happened and I started to feel like I was working against the shoes for the last 5K of my run. I was able to talk to a former pro runner sponsored by Nike and a pro triathlete at our Team Tri Camp a week later. They had worn out multiple pairs of all three shoes. They mentioned that the Nike shoes have an S shaped plate that pushed you backwards if you are a heel-toe runner but that there are other brands of carbon plated shoes that have a C shaped plate. The C shaped shoes tested really poorly in the studies I had read but a light bulb came on as to why the shoes respond so different for different people and what I had experienced in the shoes. At tempo speed and faster I strike at the mid-sole but on my long runs of more relaxed paces I strike at the heel and roll to the toe. So for the Nikes to work for me I have to be going at tempo pace or faster. At my marathon the next week my average pace was 21 sec/mi faster than my goal pace. I made sure I was never anywhere close to dropping below tempo pace. I PR’d by over 20 minutes in the Marathon and was first place overall Master. So for my first pair of Nikes in 25 years I was very happy. Note: The former pro runner at my team camp didn’t like the Metaspeed Sky. I was not surprised since he is a Nike guy. He said that the Nikes were just a better put together shoe. I think that if it had been the other way around and Asics had been his go to shoes for the past decade that he would have been saying that the Asics was the better shoe.
I ran a Marathon relay 7 days after my marathon. It was a ten man team where everyone ran 2.6 miles. I had done a 5K 6 days after a marathon once and the first 2 miles I was thinking the the run felt as good as any other 5K I had done on fresh legs. Then in the last mile that muscle damage came though and I was not fairing well the last mile. So I wondered if I would be able to get through 2.6 miles. I did my warm up in my Asics training shoes and my quads were screaming and very sore. I put the Alphafly on and the high stack height with tons of cushioning made all the pain go away. I ran that 2.6 mile run 7 days after a marathon at a pace that was 15 sec/mi faster than my PR 5K pace.
It took me three weeks to recover from my marathon but in the past week my run workouts have felt like they are back to normal. I have Duathlon Nationals in a month so I will take the Alphaflys out for a 5K race in 8 days to see how I do in them at that distance and what type of goal pace I need to set for Duathlon Nationals. I think It is going to be 15-20 sec/mi faster that what it was without a super shoe.
Sorry I don’t have a lot of information on the Vaporfly and Metaspeed. Here is what advise I have got on them 1) The Pro triathlete (former D1 runner) said that the Alphafly is her go to race shoe. She also said that she likes it for her long runs. She said that she will use the vaporfly in races with lots of sharp turns because she can accelerate out a turn better in that shoe than the Alphafly. All I have on the Metaspeed is that the former pro runner said that it was okay and he ran fine in it but that the Nike shoes were a better shoe in his opinion. The tests and reviews that I saw all had the Alphyfly as the top pick of the three but they all also said that they all were great shoes and that you couldn’t go wrong with any of them.