I prefer ISSPRO, but I'm just a wee bit biased
Here are the things I think set ISSPRO apart:
1. Factory dash matching - for the popular diesel pickups we work hard to match all of the aspects of the factory gauges. If you look closely at the pointer hubs, fonts, colors and things like that, we try to make the gauges look like they could have come from the factory.
2. Experience in the diesel market - we've been doing diesel gauges since the start of the company in 1949! Our products are used by OEMs in heavy trucks, military, construction/ag, and marine applications. We test at the diesel events all of you attend &/or read about in the magazines.
3. Temperature compensated pyrometers. Without this feature you could be reading over 100°F too low on a hot day and heavy load. Have I been running 1250° or 1350° as I pulled that grade for the past 10 minutes?
Finally - all of our "modern" designs (everything designed since I joined the company over 5 years ago) are built right here in Portland Oregon. Certain other brands have gone completely offshore with their manufacturing.
If you have any questions please feel free to post or email me.
Regards,
Michael Pliska