I've decided to compare a 1S to a 2S toothpick following the great videos of quad66... and thought that I would have more fun with a 2S than with a 1S... and bought the 1S ready to go (BetaFPV HX100 SE) and built the 2S.

The build:
It's a standard Toothpick with a Pickle 2.5'' frame (https://www.thingiverse.com/thing:3359505). I've bought it from TacoRC, as sourcing Kabab TP frames in Switzerland is a pain. The canopy came with the frame and is in a good quality TPU. I have other molded canopies that could fit, but that one is actually better than the LarvaX or Eachine Twigs... The LarvaX gave me a lot of jellow after the first crash. The Eachine canopy has no place where to mount the VTX antenna... Talking VTX, it's a nano400 from NamelessRC. Works very well, fitsunder the canopy, is working through the tramp protocol and is super light. What's not to love?

The FC is a crazybee v3.0. First ever crazybee board that reliably works! :D
Some remarks (please look at the wiring schematics below): There is only 1 ground pad and it's small (near the tip of the screw driver on the picture and on the schema). One should put on that tiny pad the cam, the vtx, and the receiver! I thus merged all into 1 cable, following a trick given by Nick Burns in one old build video... Works well. The 5V is immediately next to the ground and it's quite a packed area... I thus connected the vtx to that point... and on the vtx I connected the camera (see schema where my tweezer is). This works well and you can have relatively short cables. This being said the soldering on the NamelessRC VTX is painful! It is so small! Smaller than the smallest tip I have for my iron!
Now the motors... Amax 1103 7500 kv (beware 3 screws only!!!!)... These are among the nicest motors I ever bought for my micros. You feel no notch when turning them... and they look good! One point they don't come with a plug... So direct soldering on the pads after removing the plugs from the crazybee board. I need to warn pretenders: I've torn one pad while removing the plugs! These are not great quality... and that's why I soldered from the top. There's quite some heat going there during flight, as 2 pads soldered one another... So beware with your soldering and plug removal.

Weight is less than 50gr... Yeah

The flying
The 2S flies like a toothpick : lots of power, super smooth and agile. As expected it hovers around 30% throttle... I've started with the 65mm props but quickly replaced them for the Avan 2.5''. The latter is less noisy, which is good in my garden, and less speedy while maintaining the agility. Good for my garden :) When I fly in larger spots, I'll likely put the 65mm back on. Flight time is 3:30-5 min, depending on my rage on the throttle.

If you read all that you may be interested in the 1S... So here you go.
I got it a few days back. It flies with a 300mA 1S battery... and it is fast and fun to fly! I never thought I would like it that much :)
If you take the 2 quads, the 2S is a little heavier (like 10gr more without the battery). When you add the battery, the 2S is 65ish grams while the 1S is below 50gr. This you can feel on the sticks.

I have better throttle management on turns with the 1S... Like you can come slightly higher and smoothly turn while going down. The 2S would go down faster requiring more throttle management...
Naturally the 1S does not shoot for the stars like the 2S... but it is still very acrobatic :) I can throw everything!!!
Speed wise, they seem about the same. That being said my garden is small, so, no real speed run possible.

A big comment: The canopy has been improved by BetaFPV. This is not the crappy breaking canopy anymore! I discovered that after having put some glue on the back and having doubled it with another transparent one... Yeah!
Finally one of the nylon screw in the kit is not exactly M2 and the nut did not hold. I had to glue one of mine...

That's about it :)