There are really two varieties of console-emulation plugin.
 
Cakewalks, and third party ones like Waves' NLS, which put simply emulate the changes made to audio by passing it through a high-quality mixer channel with flat eq, tend to be subtle. To really hear them make a difference it's best to have lots of tracks and busses using them. Which isn't surprising really as they are based round consoles like the SSL and Neve ones which were designed from the off to be as "pure" as the technology of the time could manage. Ironically, it's their lack of purity that's ended up making them and their sound so sought after. A bit like when CBS decided to modify the Fender amp designs to get rid of the "nasty distortion" only to find out audiences and guitarists alike actually liked and wanted the distortion.
 
If you want to find out what such emulations are doing, load a project with a lot of audio tracks, add the CE to each channel and bus, group all the CEs (or have them as the only effect) then bypass them all either by clicking on a group member or hitting "E" to bypass all effects.
 
The other kind of console emulator are plugins like Waves' Abbey Road REDD and TG12345 which, like the vintage consoles they're modelled on, have a pretty obvious and distinctive effect on audio.

Tape emulations have their uses I find, particularly if I'm trying to capture the sound of a time period when tape was used. Again, the tape recorder designers and manufacturers put a great deal of effort into making their products as hi-fi as possible so unless you crank the emulated wow and flutter and push the gain and saturation hard you won't hear them making much difference until you've quite a few channels using them.
 
Taking a track with a tape emulator, bouncing it, inserting another tape emulator on that track, bouncing that and repeat a couple of times is a way to emulate the old practice of repeatedly bouncing sub-mixes down because the tape deck was only four or eight channels in the first place. If you want recordings that sound like the 1960s repeated bouncing can give you the Beatles/Stones etc. sound in a DAW.
 
Ironic really. Back in the pre-DAW days engineers would have loved to be rid of the "negative" side of noisy consoles with less than flexible eq and tape machines with all their problems. Now we seem to want the "defects" back because they actually sound pretty good.

yea,
to me,
the whole idea of tape emulation and console emulation is @ss backwards.
 

Thanks for all the answers guys...whilst everyone was answering I was actually mixing lol...I've opened up the links that have been posted will digest what has been written.
 
After experimenting last night...I found them even more useful.
 
Cheers Ben

I think it can be fun too put a little tape hiss on the count in for a track. We all recognize it and you don't have to leave it on.

I like saturation from time to time too.

Oh I forget to mention that last night whilst experimenting with the console emulator...I discovered that changing from peak to rms actually changed the tone too...as you would expect the peak was faster when it kicked in and rms was slower...very cool!
 
Ben 

Jeff Evans
after all he loves Tangerine Dream so that says it all for me!

Haha! Thanks Jeff... Made me laugh that 
 

Jeff Evans
If it is so subtle that you cannot hear it then you could argue that it may not be necessary.
 

Yeah, this is where I am coming from I think. And at my age (55) it is now unlikely that I can even train my ears to hear any subtle nuances brought by console emulation. And I am deaf to anything over 14kHz...
 
I am somewhat envious, at times, of peeps that are able to hear things I just can't, and not just in relation to some of the things being discussed here.
 
 

My tinkering has confirmed to me that the console and tape emulations are simply distortion engines with attractive user interfaces. I have several to experiment with and they all colour the sound in different ways. It seems that humans like sound that is less than pristine but I've no explanation.
 
The emulations in Sonar are not as heavy handed as some others out there but all I can say for sure is that they add distortion. I don't use them because they are so subtle and when I want to smear the sound, I want something more intense. 

I always find it kind of humorous that people search out tube amps, tube pre's, tube compressors, etc, in hardware. They pay thousands of dollars for this high end gear, because it colors (distorts) their sound in a musically/ ear pleasing way....but then don't care for a software plug in which mimics the same colorization.

I remeber reading where years ago, at the birth of the guitar amp, where Fender was trying to eliminate distortion from their amps. Except that guitar players liked and wanted that overdrive tube colorization.

I say if it sounds good to you, use it.

I have referenced this video by Craig Anderton to better understand the Console Emulator.  He did a better  job explaining it than the Bakers did,
 
Sonar Console Emulator demonstration by Craig Anderton

Just a suggestion to anyone who may be also trying to make a decision to use console emulation or not- 
 
If you happen to be using Sonar Platinum the mix scene save is very useful. Simply save a mix scene before you add the emulation and then add console emulation to all channels. The save another mix scene with the emulation...you can try this with all three emulations to see which you like best and easily A/B between them.
 
I think the best results are cumulative as Dan Cumpian mentioned not long ago. I was on the fence with using the emulations until I heard the results all added together on each track. Now I generally add consiole emulation to each track and Tape emulation on the master.Makes a nice glue and adds some pleasant harmonics.