Have used both you asked about. Very similar in both feel and size.
S2X for me, the trigger improved also alot with minimal use. Ive left it as is, Xtreme medium springs 10lbs recoil spring (AU barrel/long slide). It lights off anything and is very smooth and nice, absolutely no problems putting the DA shot where it needs to be.
The trigger debate can get a bit silly sometimes.
The shadow 2 is most comparable to a Stock 3 Xtreme.
In markets where they are equal price, I'd pick S2.
In markets where the tanfo is significantly more expensive and your on a budget, shadow 2 represents good value or a S3X.
All 3 are good to go.