Can either of these be fair? Are their cool factors worth the loss of "fairness"?
edit: now with not broken images!
I think it really depends on your cube, in the case of Show and Tell. It -can- be a fair card, but that all depends on the threats you have to cheat in with it, and the answers you have to those threats. For example, Show and Tell is in my cube, but my cube is heavily specced for answers, almost to the point where Show and tell is a trap. Almost.
Threats to cheat in with show and tell (note that there are smaller value creatures you can throw in, but these are the ones that you really wanna get out there.):
Elesh Norn, Grand Cenobite,
Angel of Serenity,
Inkwell Leviathan,
Consecrated Sphinx,
Griselbrand,
Sheoldred, Whispering One,
Inferno Titan,
Woodfall Primus,
Terastadon,
Dragonlord Silumgar,
Dragonlord Atarka,
Sphinx of the Steel Wind,
Blightsteel Colossus,
Myr Battlesphere,
Kozilek, Butcher of Truth,
Ulamog, The infinite Gyre,
Emrakul, The Promised End,
Sundering Titan.
Answers to said threats (I will not count counterspelling Show and Tell, as that much is obvious. I am also not including simple 'destroy' removal, as it does not deal with all threats effectively.)
Karakas (some)
Dragonlord Silumgar
Oblivion Ring
Council's Judgement
Banishing Light
Faith's Fetters
Fiend Hunter
Path to Exile
Swords to Plowshares
Unexpectedly Absent
Condemn (allows attack, so 2 Eldrazi titans 'get through.')
Control Magic
Treachery
Sower of Temptation
Vapor Snag
Into the Roil
Sheoldred, Whispering One
Song of the Dryads
Crackling Doom
Brutal Expulsion
Dack Fayden (some)
Reflector Mage
Duplicant.
Tl;dr, I think it's fine of the "answers" meet the "threats" fairly. As the threats increase in power, so too must the answers. Answers that you can Show and Tell in (O-ring, Duplicant, etc.) are vastly preferable but even StP can 'negate' the advantage of a Show and Tell.
I think Berserk is fine if you aren't running infect. It's efficiency matters less in draft than in constructed, and I don't think it's so much better than, say, Bloodrushing a Ghor-Clan Rampager. It can get a little dirty, but you -do- need to pump the target first to make it worth it. The destroy clause helps balance it.