You're more likely to hear complaints about connecting to back-end transaction systems if you're using .NET, according to a recent survey by Evans Data. .NET developers are also more likely to blame changes at the application level and back-end for slowdown than Java programmers.
Admittedly, that's not the main point of this Enterprise Systems article covering the survey, but I thought it was interesting and it relates specifically to integration, so I'm starting there.
Don't pat yourself on the back too soon if you're Mr. Java, though -- the survey found Java users are more likely to find fault with JVM or architecture issues than the .NET CLR users. Java coders also seem to generate or encounter more bugs and "disproportionately cite memory leaks and out-of-memory conditions as triggers for application failure," according to the article.
To my mind, those data points actually illuminate this Evans Data finding: While the survey found .NET is besting Java in enterprise adoption this year, a majority of respondents say they're supporting both. The Enterprise Systems article quoted industry veteran Jasmine Noel, a principal with consultancy Ptak, Noel & Associates:
"An increasing number of enterprises are realizing the benefits of deploying applications built on both .NET and Java. However, with those benefits come the challenges of managing a heterogeneous environment coupled with the unique issues of both development architectures."
The trick with that approach, it seems to me, would be ensuring you're offsetting the problems of one with the strengths of the other rather than just doubling your problems.
Overall, though, most companies plan to invest more in .NET than Java. Three-fourths say they'll spend more on .NET and half of those surveys say they plan to add additional .NET staff, according to the article.