The Ventum One: well, the whole front end. At least Dimond figured out the front brake...Ventum didn't even get that far. Complete China carbon trash.
They are both SO expensive. I mean, way way more than a Speed Concept expensive.
Both companies have incredible aero data -- I say that literally. Ventum continues to go to a shit wind tunnel and refuse to release data; Dimond's release here stinks to high heaven...oh great, fantastic news, now it's much much faster than a P5-3!
Given all this, why would anyone buy one? Well, dentists need to show off their uniqueness. That's about the only reason I can think of. If you have that kind of money to spend on being unique, why not just custom paint a P5?
I saw this classifieds ad the other day for a Dimond. The guy said he not only bought the bike because of Jordan Rapp, he also bought the same size (dude was 6'3") and couldn't get the bike to fit. Perfect Dimond / Ventum customer: complete idiot sheep.
I've always liked the look of the Dimond but two things turned me off... the original fork was just hideous looking and didn't match the bike and the space behind the steerer tube. The solved both of those issues for me with the Super Fork and this Beam Box widget. I like to buy a new bike every three years or so and my recent history was a 2009 Felt B2, 2011 Trek Speed Concept, 2014 Trek Speed Concept (bought in 2013), and most recently a 2016 Dimond. I just wanted one so I got one.
To address some of your points and how they pertain to me:
1. The trainer issue. I never ride my tri bike on a trainer. I can ride in the aero position for 99% of an Ironman but can't ride for 10 minutes in aero on a trainer so I scrapped riding a tri bike in favor of a roadie on my trainer many years ago.
2. Seat post. I didn't have to cut mine.
3. Two bottles for training. I agree this is far less than ideal but there are ways around it. A double bottle holder behind the seat option would give you four bottles (with BTA and down tube options). I'm only training for 70.3's for the foreseeable future so not much of a concern for me at this point.
4. Yes, it's expensive but it's my money.
5. Aero data. Dimond has been doing a lot of testing in the A2 tunnel the past few months. I'm interested to see what gets released. I actually saw this data about the Beam Box several weeks ago but I don't think it was for public consumption at that point. Obviously, this data was released to sell the Beam Box. Nothing more, nothing less. Dimond has done a bunch of other testing far beyond this widget though. My understanding is there's some good data coming but I guess we will wait and see. I hope they just release everything (or most everything) and let us dissect it up. I just hope they don't do what Ventum did and say we have this awesome data and never release it. At least Dimond went to A2 and not Faster.
6. I bought one because it is different from other bikes. Bikes are my one guilty pleasure in life. It's also a very comfortable riding bike. I have it setup fit wise almost identical to my Trek SC, and it does ride smoother than the Trek. I'm not sure people are buying them because they're trendy... wouldn't that be why everyone and their grandmother has a P5 or SC or Shiv. Dimond is a boutique bike, and comes with a boutique price. All and all, there are not a lot of Dimonds out there. I live in the Houston metro area and I know of four of us that have them.
7. Height is certainly only one piece of the puzzle when it comes to fit but all things being equal I don't see how someone 6'3" tall as Jordan or the other guy can fit on a Size M Dimond. I would think that frame is too small for someone that tall but with the many different bar and stem configs it's probably a workable solution. Jordan seems to make it work. The other guy couldn't. I'm 6' and I ride the M size and it fits me perfectly. I knew it would fit me great going in since the size L Trek SC and size M Dimond have identical geometry.
Finland 70.3, Lahti, Finland, June 30th | Jonkoping 70.3, Jonkoping, Sweden, July 8th | Augusta 70.3,
September 23rd | Waco 70.3, Waco, TX, October 28th | Cartagena 70.3, Cartagena, Colombia December 2nd
Gear: Dimond Bikes | Desoto Sport | Hoka One One