The Ascent has an oven that is constantly on, whereas with the MFLB you can control the heater with the battery. The biggest distinction other than the Ascent always being on is going to be the temperature control. While it will always vape your herbs, you can control the temperature at which you want it to do so. So for movie theater smoke buddy situations, a low temp on the Ascent should prove itself discreet enough for you for sure.
For multiple sessions with one load, you can use different temps. You can start really low at around 340-350 (some people will even go lower) for a few inhales then turn it off. When you want another session just bump the temp up 10-15 degrees and you are good to go!
For muti session loads:
I've been using a 20~30/80-70 mix of bubble/extra fine ground bud.
I use extra fine mesh screens both at the bottom of the bowl and right at the stem screen.
I've shared this picture in the past of the bowl screen (I hope some of you folks implement this):
So what I do for my multi session bowls is:
1) Turn on the Ascent set to max temp.
2) Let it heat up to mid way, then start taking ultra slow hits.
This seems to allow the load get uniformly warmer quicker because you are helping the heat pass through the load. You're also getting the effects and flavor of the low temps.
3) Once it hits max temp, I let it rest there for around 10-20 seconds then take one massive draw.
4) Turn off the Ascent
5) Take about 3-4 draws which depletes the load and bowl of the vaporizing temps/heat.
By using this technique, I get around 2-4 sessions out of a bowl.