While I've long debated the real value of professional certifications in the IT industry (I've known numerous highly-certified ignoramuses), it would be ignorant to refute the hard data that demonstrates the perceived value of certification and the resulting remuneration benefits.
Further, not all certifications are alike, and since I have approximately a dozen certifications myself, I can tell you conclusively that some effectively demonstrate proficiency, while others are barely worth the paper they're printed on.
This blog topic was actually prompted by a very interesting post at TechTarget entitled The Value of the VCP (VMware Certified Professional). Personally, I believe the VCP is amongst a very few certifications that do a good job of testing and proving proficiency.
In his post, Joe Foran draws the conclusion that the single-test VCP certification by itself actually holds more value than any other multiple-test vendor certification (including those from Red Hat, Citrix and Cisco)! Joe's post was certainly an interesting read, and if you plan on pursuing professional certifications, you owe it to yourself to pay attention to his sources.
😉 Disclaimer: I am a VMware Certified Instructor, and teach VI3 VCP courses. So, don't just take my word for it, do your own research.