Got the Gen10 to join my N40L this week. 4x3TB Ironwolf arrived today.
Impressions:
Pros
Fast. Streets ahead of the N40 and even the G8 which I have at work feels slow
Build actually better imo. Yes, it's not as upgradeable CPU wise but at the current price of £160 including cashback and 8GB DDR it's still a better choice than the G8 imo.
Lots of free room inside to mount extra hardware
2xDP and 1xVGA is excellent. I just bought a DP to HDMI cable and connected it up to my Dell, using OSD to switch between the two. Runs another monitor on the other DP just fine.
5th SATA port makes install a breeze
Cons
Don't buy it if you want to run ESX with storage passthrough as it doesn't work (and is unlikely to given it's a Marvell controller). ESX 6.5 does load and run without any other issues I can see. I specifically wanted to get conversant with HyperV instead so it doesn't worry me
Old P series raid controllers from HP don't work on Gen10. No cheap high spec raid

DDR4 is expensive
I think overall it's a worthwhile deal.