It is extremely difficult to get a CGC 10 and once we see their population report, I think the prices of 9.5s from CGC will see a boost
If the creature you control is an illegal target, you won't put a +1/+1 counter on it even if it's still on the battlefield
In formats like Pauper, where all dual lands are tapped lands, they are one of the best land cycles in the format, with a whole deck (Skerd) being built around them
Lifegain effects fall into two categories: single-effect, big bursts of lifegain from cards like Feed the Clan, and incidental lifegain from cards like Soul Warden and Kambal, Consul of Allocation
the abilities combine to bring the creature back with both a +1/+1 and a -1/-1 counter, which cancel each other out leaving you with a Putrid Goblin with no counters
The game is sold primarily in two different ways, either as 60-card starter decks or as 12-card booster packs