Sound bar versus surround system


We are going to install a modest TV and sound system in our very large bedroom to watch movies on and a bit of programed TV. I have everything I need for a surround system (center channel speaker, main speakers, rear surrounds and sub) but no reciever/processer, but I’m interested in a compact system, and have had no experience with ’sound bars’. My question is this: How do sound bars compare to say a center channel and main (mini monitor) speakers? I have two different dedicated music systems so serious music listening is not going to happen here.
Can you play soundbars at realistic listening levels? Do they give you OK stereo separation? I assume a sub would be needed for bass reinforcement.
Looking forward to your feedback, and thanks.
rixrax
For the bedroom a sound bar is fine, I have a few Samsung systems and they sound as good as my Maggies for TV stuff. 
I have a high end surround system in our living room and a sound bar in the bedroom. While sound bars are not surround system… they can be really useful in bedrooms. They can simulate a much bigger and complex sound in the front. You need one with a dedicated little subwoofer. It is definitely a trade off but even with wireless speakers you end up with a bedroom full of boxes. A good sound bar can offer highly detailed natural sounding speech and music for your movies and shows. As always research and more money buys you more betta sound.
You say very large bedroom, how big? In order to come close to realizing the sound of a movie soundtrack, you need at least 5.1, with 1 sub minimum.
Agree with fiesta.  You want sucky sound for your bedroom, like perhaps there may be other entertainment options for that area , get a sound bar.  Serious HT?  Do at least a 3.1, 5.1 would be better
“Can you play soundbars at realistic listening levels? Do they give you OK stereo separation?”

The answer is Yes! But you need to choose wisely. If you go for run of the mill ‘boxed’ surround set from Sony, Samsung, Vizio then you’re in for sucky experience. Look into surround bar options from SONOS. You are going to experience a very high quality sound from movies and music (streaming). SONOS cover shipping and returns and gives you 45 days to audition. 
https://www.sonos.com/en-us/shop/arc.html

I’ve been using the same SONOS surround system in my living and bedroom for last 14 years.