I got some testing done with BYE and CR2 RAW files. Instead of doing 3 minute subs I did 30 second subs to speed up the testing.
Here were my expectations. I was going to take 30 subs of thirty seconds each at ISO 1600. This would equal 15 minutes of image data. If I tacked on another 2 seconds to each image for download time this should take 16 minutes for an imaging session.
The first run with BYE I had all the bells and whistles on. I was reading and writing Exif data. This gave nice little readouts of the sensor temperture, local weather for temp humidity and other things and imbeds this information in the image file. Nice if you care. First run began at 12:33 am on the dot and finished at 12:57.20 am. The image session to get 15 minutes of data took 24 minutes and 20 seconds! 8 minutes 20 seconds longer than expected!
Next I ran BYE with the read and write Exif data skipped. It helped a little. Start time 1:04 am on the dot. Finish time 1:26.05 am. 6 minutes 5 seconds longer than expected with a total time of 22 minutes 5 seconds!
I ran EOS Utilities next using the same parameters. There is nothing to turn on or off with EOS Utilities. Start time was 1:29 am on the dot and finish time was 1:45.15 am. 15 seconds over the expected time of 16 minutes, allowing for 2 seconds between subs. Brutally effecient! No bells and whistles. Just a Utility like it says.
To me the fancy dashboard skin, weather readouts, sensor tempertures, multiple thumbnails, RGB histograms, are not worth standing outside for another 6 to 8 minutes when it's freezing cold.
I think BYE makes a fine focusing tool and that's what I will use it for but for the actual image captures I will use EOS Utilities for now. Matter of fact is, EOS Utilities can focus quite well also using live view and software zoom, if you have a bahtinov mask (or not).
I will test JPG's soon to see how that works just for those who do not have software that handles RAW images (Like Registax) or RAW to TIFF conversion. Some times one has to process just JPG's like the time I forgot to change my camera settings and had 150 3 minute subs! A whole night of imaging, I wasn't gonna waste the data by not processing it!