If we can compare it with 100 meter sprint, clearly http was the one who started first. Then, dominated by the rtmp/rtsp up to 80 meters. Now, approaching the finish line, http is picking up the distance with amazing speed and almost tied. Still, rtmp/rtsp seem to be ahead of the race. But http may end up winning the race.

HTTP vs. RTMP

	HTTP	RTMP
Server Components	Open	Specialized
Security/IP Protection	Basic	Enhanced
Caching/Scale	Native	Specialized
Player Interactivity	Basic	Extensive
Multicast Support	N/A	Supported
Plug-in Penetration	Nascent	Extensive
Firewall (port/protocol)	No restrictions	Some restrictions
Variable Bitrate Support	No impact	Susceptible to data spikes

Table source: ref.1

Conclusions from others sources:

So picking a delivery method may not be as easy as picking the color of that new car. All three major ABR technologies have their benefits and risks. Adobe's Flash is the ubiquitous choice for video-on-demand (VoD) and has tremendous penetration on the desktop. Microsoft's Smooth Streaming has had some early live event successes, and it helped provide video for the 2010 Winter Olympics. Apple's HTTP Live Streaming is available on 25 million handsets, but it has limited desktop reach and longer latency and startup because of the data network it operates on.

Ref. #1

or

Again, RTMP distribution is still widely and beneficially used by many websites today. However, while there may be little impetus for some sites to change, at this point if you're considering a streaming technology, the overwhelming sentiment is to deliver via HTTP. Of course, for adaptive delivery to Apple devices (and Android 3.0 and higher), HLS is your only option.

It's also useful to recognize that most video content is delivered via plain old HTTP progressive download. Sure, there are limitations, like the lack of adaptive streaming, but you can't say it's worked out too badly for YouTube, who delivers about 70% of video over the web, exclusively via progressive download. However, this approach prevents YouTube from deploying the digital rights management (DRM) techniques available via HDS, Smooth Streaming, and HLS to protect their videos, which is a key reason sites with branded content use these technologies.

Finally, the focus of this article has been general internet streaming. Particularly for intranet use, streaming-server-based protocols like IP Multicast and applications like peer-to-peer delivery provide lots of value and even more promise. So don't throw out the baby with the bathwater; streaming servers aren't "bad" and HTTP isn't "good." Rather, choose the best tool for the job.

Ref. #2

In my opinion, here are the best articles describing the two competing technologies:

1. HTTP versus RTMP: Which Way to Go and Why?
   HTTPvsRTMP.pdf
   - from Cisco


2. What Is a Streaming Media Protocol?
   HTTP, RTSP, RTMP, Smooth Streaming, HLS, HDS, and more:
   What exactly are streaming protocols, and how do they interact with other communications protocols?
   What Is a Streaming Media Protocol?
   - from http://www.streamingmedia.com/