I played a tourney yesterday with Sneasel and these boogers. These
cards are stout. I was playing others that had them,too, and I was surprised
by the difference in usage by the respective trainers. These two cards won
me games solely by letting Sneasel live.
My First Rule of usage is to only play it when you are gonna use it
after YOUR turn. I treat it like I treat Plus Powers. I save all my Plusses
for the KillShot. Of course Oaking is the exception and that is basically
the case in utilizing Berrys. The Logic being that if I see a Berry attached
to a Pokemon I wait until I have enough to do it before I kill it. Like my
opponent attaches a Gold Berry to his Scyther with 1 counter on it so I
sworddance with my Clefable. Next turn I do slash for 60 and kill it and
Gold Berry is wasted. If he held it in his hand then I just woulda slashed
for 30 and he coulda attached the Gold Berry and cleaned it off after his
turn. Always try to surprise your opponent.
The ONLY other exception is Poison. Depending on the order of turns,
it may be necessary to use Berry after your opponent's turn therefore you
have to attach earlier than I like and hope for the best. (An Aside: I got a
ruling from WotC that says if poison will kill your pokemon at the end of a
turn and you have a Berry on that pokemon that you are allowed to activate
the Berry before the poison damage is done... I wholeheartedly disagree for
the simple reason that poison is attached at the end of a turn and that the
berry is activated between turns, so I think poison goes first. Any
Thoughts?)
My Second Rule is to look at your pokemon before you decide to add a
Berry or Gold Berry. Remember that the card states you HAVE to have 2 or 4
counters on your pokemon before you can activate. Do not attach a Gold Berry
to a 50 Hp Pokemon. There is little chance it would be of any use.
It is important to try and figure out what Pokemon you WANT to save
when building your deck. I submitted a Meganium/Exeggcutor deck and
obviously I want to save the Exeggcutor before all else (the Meganium is
there to double up Exeggcutors potential strength). So I went heavier on the
Gold Berries since Exeggcutor is an 80HP Pokemon. A built-up Exeggcutor is
the focus of the deck and that is why he has to be saved. I can turn him
into a 1 kill per turn monster and that makes him too valuable to lose.
Conversely, if Ditto was my Big Dog than I would go with Berries and
Potions.
Third Rule. Just because you have a Berry in your hand you do not
HAVE to play it. This is sorta an addendum to the first two rules. Save the
Berry for when it can be used. Save the Berry for a Pokemon you want to
save. You have to get a feel for when it would most benefit you. Patience.
That is the hardest thing to learn. Few games can be won in any given single
turn. Battles CAN be LOST in any given single turn Think long-term before
you over re-act.
My Fourth Rule. Why. EVER, would you throw a SuperPotion into a deck
if you have less than Gold Berry? It makes no sense and just yesterday this
happened against me. In fact, he had attached a Gold Berry to Scyther the
turn before and then uses Super Potion and leaves the  Gold Berry still
attached. This is the same sequence as the example above. I won that round
2-0. If I didn't I shoulda been keel-hauled.
Lastly, a neat trick. It worked great yesterday. I had a full bench
and a Sneasel active with a lone Dark Energy attached and 30 damage. He had
a Steelix (that was worrying me) with a DCE, a Steel and 60 Damage. In my
hand I had another Dark, a Gold Berry, a Plus Power, a Rainbow and Oak. So
what did I do?
a) attached the Rainbow. That gave me the chance to
do Beat-up. Also gave me 40 Damage b) then attached the
Gold Berry since I was now able to clean him off at the end of turn.
c) attached the plus power so it would take only 2 instead of 3 flips to
kill it
d) announced I would Gold Berry between turns and
did beat-up.
e) lost the first 3 flips
f) started to feel sick
g) won the next 2
I accomplished 2 things that turn. I was able to clean off Sneasel
(only because I attached the Rainbow instead of a 2nd Dark to set me up for
the long haul) and went for the kill at the turning point in the game.Also,
I was patient enough to attach the Dark energy next turn and then Oak.

I enjoyed that. Feel free to e-mail me at Mark.Dawson@vacorp.com.
Later Gator