So when you set a send level of 0dB to a 100% wet effect return, post fader, does that mean the effective dry/wet ratio is 50%?

@Bristol    
Track output goes to Master, which goes to Main Outs
Send output to Reverb Bus, whose output goes to Master ...
 
 

I looked more into this and it bothered me so much, that I downloaded a demo of ... Cubase  (Sorry!) ... just to check it out there.    
 
I quickly added an audio track there, and added the insert reverb and it sounded ......... PERFECT!
 
Back in Sonar, it was sounding not good at all on the insert.
 
If anyone is familiar with Aether, it displays input on a circular meter.  In Cubase my insert track showed input all round the circle, but in Sonar it showed input only on the LEFT hand side of the circle.    I still heard sound in both side of my headphones, but soething surely is wrong somewhere.   All other settings as far as I know are normal.   I do not know, but maybe its a mono/stereo issue somehwhere ........ how can I go about troubleshooting that?
 
Please don't make me buy Cubase ... ;-)
 
 
 
 

When you insert an Effect in the tracks effect Bin, the signal will pass 100% through that effect. this is desirable for things like EQ and Compression. Normally we would not put things like reverb there. Reverb often needs to be shared by other tracks and it helps to keep your sound all in the same "room" by only using one instance.  
My guess is the difference you are hearing is the effect has some sort of EQ involved in the settings. Reverbs often do. This is for good reason when we don't want to process say, the lower frequencies. 

I can't say I've ever noticed any great difference between an effect on a send or on the track insert. Perhaps there's somethjing else going on with the track? Having said that I rarely, if ever, use reverb on a track. It's nearly always on a send for me for the reason JohnnyV mentions.

Dude, if you can't suss out how a send/return works, it doesn't matter what DAW you use. 
 
The obvious answer here is "use your ears". Keep dialing the send controls and the verb controls until you reach a sound you like. There's no perfect recipe for that stuff, it's totes subjective.
 

ULTRABRA
If anyone is familiar with Aether, it displays input on a circular meter.  In Cubase my insert track showed input all round the circle, but in Sonar it showed input only on the LEFT hand side of the circle.    I still heard sound in both side of my headphones, but soething surely is wrong somewhere.   All other settings as far as I know are normal.   I do not know, but maybe its a mono/stereo issue somehwhere ........ how can I go about troubleshooting that?
 
Please don't make me buy Cubase ... ;-)

Check the send's pan setting and check the buss the reverb is on to make sure you added a stereo bus.

@ ULTRABRA
Have you tried the stereo interleave button on the mono vocal track?  If you turn on the stereo interleave, with the reverb as an insert, does the Aether 'circle' show on both sides?

Thanks for all the suggestions/ideas.
 
@Jean:    Yes, that was it!  On the mono vocal track the stereo interleave was on mono.   Changing it to stereo fixed the issue.  Thanks so much for that.
 

I always appreciate it when someone acknowledges pilot error instead of just disappearing from a thread they started. I think this kind of input is very helpful to those learning about computer-based recording.