We’ve been working with ESRI software for more than 7 years now. From a pure business perspective, there are many reasons Latitude has focused mostly on ESRI products. But it's not the business side that excites me -- it's the technology. Here are a few reasons I like ESRI technology:
Web ADF - I recall last summer sitting down with Steve to discuss some of the technology I played with while down at Redlands participating in holistic testing. We started chatting about Web ADF and, as I always do, I tried to think of a meaningful analogy to communicate what I thought the signficance of Web ADF was - it went something like "ADF is to ESRI server technology what .NET is to Microsoft technology." You could sit down and write all of the code necessary to incorporate ArcIMS, ArcGIS Server, OGC, and others and build a framework for map navigation, tools, querying, etc, or you could build on top of Web ADF, leap frog all the up front development and focus on your real business challenges. It's relatively new technology and has some wrinkles to iron out, but I believe it will become a core asset for ESRI. And based on discusionss I've had with Redlands, they seem on top of emerging .NET technologies for the .NET verion of Web ADF. We're putting our money on the .NET ADF.
ArcObjects - ArcObjects is perhaps the largest COM implementation in the world and has to be the most feature rich GIS library available. Put that into a server context and you've got the makings of a pretty powerful web GIS engine. Now, ArcObjects isn't the easiest, most intuitive library to program with, and it wasn't originally designed to run in a server context, but it is certainly stabilizing and we should see big performance jumps with the 9.3 release. Also, having ArcGIS Server powered by ArcObjects means that as the desktop GIS functionality matures due to technological and user driven innovations, so will ArcGIS Server.
Supporting Technology - It always amazes me how much effort ESRI goes to to support their products on so many different platforms. Windows, Solaris, Linux, Java, .NET, ColdFusion. Sometimes you get the feeling that they bite off more than they can chew - but I would rather have the option to run on my platform of choice than not run at all.
User Community - All it takes is one trip to the ESRI International User Conference or even the Developer Summit in Palm Springs to realize how many like-minded developers there are out there trying to build the same stuff you are. Or do a Google search for some Java or .NET technology only to find a bunch of hits pointing to GIS developer problems. Bottom line is that if you're struggling with an ESRI programming challenge, someone has probably solved and posted about it.