Yeah I also noticed less exhaust smoke and less soot % in my oil analysis too. HPR definitely does burn cleaner because it is a purely parrafinic fuel missing nearly all of the aromatic hydrocarbons found in Diesel #2. I used it for almost 50K miles in 4 different vehicles, some tuned and others completely stock. I made a post on here about the 70/30 blend based on a research paper I read. I wondered if you could alter the injection timing, like retard injection slightly to compensate for the earlier ignition with the high cetane based on a technical paper I read. How with tuning on a modern CR diesel, you could alter the timing to increase cylinder pressure and optimize the engine specifically for HVO. Never tried the 70/30 blend as it is a hassle to fill up twice when you need fuel.
The incompatibility with older rubber seals is well documented on here. If you haven't had any fuel leaks yet, I'd be prepared financially to deal with them in the future.
I started using a fuel additive blended 400:1 that gives similar performance as HVO when mixed with CARB DIesel #2. Low smoke, low soot, 5-7+ Cetane Boost, Lubricity etc... that gives me all the advantages of HVO without the negative impacts like lower fuel economy and loss of low end torque. In fact, my oil analysis soot % is actually lower using dosed D#2 than with HPR. Quality Chevron #2 plus additive @ $0.10/gallon is also cheaper in my area than buying propel HPR. I'll be using the dosed dino juice until given no other choice by Gavin Newsom and the green police.
HVO AKA Renewable Diesel typical fuel properties in case you're curious