I have a pair of ses 4.5 to compare these Pro wheels too and have used both extensively so I am able to compare them both more objectively.
For starters, I use the same tires for both (pirelli p zero race tlr 30mm), I use the same amount of sealant (silca, ~70ml), and I wheel balance all my wheels (weights under rim tape to counter balance valve weight). The Pro wheels spin very nicely down hills, they are definitely responsive and you can feel it in the saddle as well as out of the saddle compared to the ses 4.5. I think getting the weight to be sub 1300g for this depth is pretty incredible given Enve didn't go carbon spokes. This is great because you can get it serviced anywhere without needing any special tools or process and getting replacement spokes (which it comes with) won't cost an arm and a leg.
The one catch is maintaining speed. If you think about the physics, if you think of a wheel as a flywheel, a heavier flywheel will use more energy to spin up however less energy to maintain it's speed once it has spun up, while a lighter flywheel will do the opposite, faster acceleration but with more difficult to maintain speed given how much lighter the rim weight is. In this era where everyone is trying to produce lightweight 50-60mm deep wheels under 1300g, I always did wonder at what point does the wheelset being too lightweight become a problem and I think these Pro wheels are at the absolute limit. Anything lighter and I believe they would just be too unstable (due to crosswinds), too light to maintain any fast speed and too physically weak (if you want the occasional off-road fun on light gravel or going over big holes in the tarmac).
Does that mean these wheels are not great? Definitely not, they are exceptional in their own way, very well built, and I love the silver spokes and hubs however the question really is are they worth $1k more than the standard ses 4.5, and to that almost always I would say no. The ses 4.5 just feels more bulletproof, they are the kind of wheels where I could go over any pothole, speed bump or gravel road at any speed and never once get the feeling of it potentially getting damaged however with these, given how light they feel I just subconsciously have that wonder of their durability in any larger hole in the road that is unavoidable.
These days 30-32mm is the standard for tire width and having the wider inner rim width of the ses 4.5 is better suited for the wider tires than the 23.5mm inner rim width on the Pros. The standard ones will be better on average than these, if you live in a hilly area, having the agility and acceleration is great because you can definitely feel the difference but if you are living in a flat or rolling hill area, I don't think it is worth the additional cost. If money is no object for you and you are deciding between the two, go for the Pros because aesthetically they do look really nice.
These wheels are not only fast and light, but they are also easier to mount tubeless tires. I have the previous SES 4.5 wheels, and these are much easier to work on.
