My opinions based on using these camera apps over the last few days.
Can't recommend Camera Awesome. After reading all the bad user experiences for this app in the Play Store for the N5, I decided to give it a shot anyway. Mistake!! More often than not, indoor pictures were horribly underexposed, all features are not available, and sometimes the flash didn't work (even in flash ON mode). Pretty much what the poor reviews said. The stock camera app is WAY better than this one, IMO.
The Pro Capture app works well and has a lot controls and functionality, but has no HDR mode (that I can find, anyway).
After taking many photos and comparing Pro Capture to the stock app side-by-side, I prefer the stock app with HDR. It does a better job at exposure compensation and white balance (more accurate lighting and color representation). If you take your time, and use the volume rocker for the shutter release, the N5 takes very good pictures. It's just not good for the 'quick shots', yet.
I haven't noticed much speed difference between the two. The Pro Capture app does have a burst mode which takes quick successive shots, but the first picture is still laggy. Since kaseyk75 has had good results with action shots, I need to spend more time with Pro Capture and compare action shots with the two apps, using the Action mode with the stock N5 camera app.
Based upon experiences with past phones (GS3, iPhone 5), I think the low light pictures with the N5 are quite good. Wife and I went to a concert, and the exposures of her pics were so bad (also an iPhone 5) that we ended up taking pics with the N5. Pictures were good, with low graininess. It takes better low light pics than my GS3 did.
So for now, I'll stick with the stock camera app. Black Friday weekend, Pro Capture is 75% off. Worth the money for the functionality, IMO.