A choice starter for decks and a solid alternative to Budew DP. Stantler has 70 HP (which is great for a Basic), +20 Weak to Fighting (not so good with Riolu and friends running around), no Resistance, and 1 Retreat Cost. Its first attack, Lead, lets you grab any Supporter from your deck for free. And if you really want/need to attack with Stantler, its second attack, Frighten Horn, is pricy 2 energy to deal 20 damage, but it causes Confusion on non-evolved Pokemon. Overall, it's a solid starter for decks who don't need a starter for searching out Pokemon for the bench.
Modified - 8/10 (Solid card, but becomes a bit of a dead draw later in the game)
Limited - 9/10 (Excellent here if you got any Supporters, but falters in value if you didn't get any. Still makes a good big Basic Pokemon though)
Unlimited - 1/10 (No real need here imo, and besides most of the best Trainers here are not Supporters)