I currently have a DJI Matrice 210 and a mate I meet at our Remote Pilots Licence course this year has a Yuneec Typhoon H Pro which is very similar to the Yuneec H520. We have taken our drones out for flight and compared them.
The Yuneec Typhoon h pro has retractable landing gear like the Matrice 600, while the M210 has fixed landing gear, the Cameras on the Yuneec Typhoon h pro are cheaper and smaller and would enable you to get more like a Thermal camera. The M210 has a good range of Camera's starting with the 4XS and going on to the X5S, X7S, XT2 [Thermal], V30 [30x Optical Zoom] yes more expensive but you have to remember the whole goal of UAV flying is to get your payload into the air which is in most of our cases Its a camera. Also the M210 has the options to mount a dual gimbal so you could have say the XT2 or V30 on the right side and on the left side of the gimbal say a Zenmuse X5S, you can also mount a camera on top with another external Gimbal that is included which you will need to use the external GPS adaptor.
The Yuneec Typhoon h pro is a Hexacopter and so would have redundancy if you lost a prop or motor however you only have one battery, where as the M210 is a Quadcoptor but has two batteries on board so if one dies the other takes over for you to RTH.
If you want a robust UAV that will assist you in your field - Heres why I would recommend the Matrice 210 or even say the Matrice 600
roof and solar panel inspections - High resolution cameras from the IP43 rated X4S to the X5S or X7S, for thermal the XT2 gives pinpoint temp warnings
transmission tower inspection - using either the V30 [optical zoom] camera to reduce the need to get close to the tower, you could zoom in on bolts or wields or even the XT2 thermal to check.
search and rescue - Just saying the Zenmuse XT2 would be amazing for this and is something I am looking at long term, set it for a certain temperature setting and it will go off when it detects it.
mapping - Using DJI Ground Station Pro with 75% frontal overlap and a 60%/65% overlap to the side and flying a predefined mission the M210 could do it fast and stable.
then overall performance, reliability - So far the M210 is a solid beast and is a lot larger that the Yuneec Typhoon h pro not sure on the size of the H520. I found that they file pretty much the same, my M210 had a lot more down draft and copied so much better in the wind with to leaning into the wind and or buffering.
The Yuneec make some nice UAV's and if you want a compact UAV that has retractable landing gear, 360o field of vision and can use different cameras, it could or would be the cheaper option, however if you want a fully Industry focused UAV that will give you more diverse possible options like dual camera, top mounted camera, IP43 rating UAV (using the XT2 or X4S) and that can withstand a bit of wind then the M210 is a great investment and its why I personally bought it over say an Inspire 2, or other brands on the market.
I hope this helps in some way, and if you already bought the H520 whats it like?