Hi there,
So coming from a UltraPure gas background, semiconductor FAB and SCADA POV
Well they are NOT really in the same league, 50 PPm with a slope more like a Hump. 48hrs to get dry’ed down vs, 100PM with a slew of <60sec, startup in clean air of 5minutes. 
one needs a Heater … No not at all even close.
Sure it will work for purely detection sort of, but in a measurement enviro , Kaka…
Check both Data sheets you’ll be enlightened. the op was asking about a comm issue not a price point…LOL 
, just messin with you…
Good stuff though.
“Simpler and cheaper” Not even, what is a matter with RS-485 (it’s VERY GOOD) the sensor you link to needs some more, a lot more to do anything close the the S-NH3-01
Not to mention the S2100 is a $70 dollar tank. No he got the GOOD industrial grade stuff just needs to connect it up correctly , I do However like the MOS sensor in the grove piece but again only 300ppm in smaller form for hobbyist, so the juice isn’t worth the squeeze so to speak unless it’s just being used for a “presence” detector.
Again his setup is out of the package ready to go, The other route needs much more and therefore cost more in the END, IMO.
take what I’m soapbox’n with a grain of salt.
GL 
PJ 