The selected printing or product matters because the same card or release can appear in multiple tracked versions
This damage may include heavy wear, creases, dents, scratches, bends, scuffs, tears, inking, water stains, and/or other types of damage
The cost-reduction ability of Sentry Bot doesn't change its mana cost or mana value, only the total cost you pay
Aside from being a human, which is a very relevant creature type in Commander, Modern and basically every other MTG format, Esper Sentinel is good because it reads: Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays X, where X is Esper Sentinels power. Its a bit like Rhystic Study, but the cost can be far higher if youve got things that make humans stronger or you can put +1/+1 counters onto Esper Sentinel