I like "farming" progressive 9/6 JOB machines where each of the top
3 prizes is a progressive. Ever since a few monkeys saw what I was
doing, the market now has new clearing price. I have to say the
best opportunity was Jackson Rancheria with IGT machines and fast
meter movements, but that too has changed. So, here's the story:
I was visiting a casino over the weekend and I wasn't expecting any
good opportunities. Then I saw a bank of $1 9/6 machines where the
quad progressives were at 40 for 1 (typically at 25 for 1)*, and I
couldn't believe my luck. The first thing I did was ran to the club
to get new player cards to get comps!! These are dollar machines. I
got back and started to pound away. Quads are special hands in that
one can get 4+ quads an hour or one quad in 4+ hours (happen to me
once on a Max machine, a bi-modal machine, and I was breaking dealt
full houses to increase my chances for a quad).
The first $100 bill goes slowly. Then I had to put in my second
$100 and this goes slowly as well as did my 3rd $100 bill. By the
4th $100 bill, I already knew I was going to have a losing session
and needed to hit the quad to minimize my loss. As luck will have
it, I started catching full houses, converting 4-card flushes, and
rebuild my bankroll. Then, to my horror, someone else had hit the
quad at 45 for 1! Urgh! How could they, that jackpot had my name
written on it.
The moral of the story is that without risk, there is no reward.
Additionally, this story supports the notion of NOT adding back the
meter movement to the game ev! Sometimes, it's cheaper to pay for a
meal, then to get a free meal via comps. Lastly, I need to check
this casino more often. 
* Let's say you use a traditional 9-6 JOB strategy for this game
WITHOUT making strategy deviations. The way I figure this game is
that for each extra 1 unit increase in quad payout, from 25 for 1 to
26 for 1, the ev of the game increases by about 23.6 basis points
(0.236%) on a linear approximation basis. If the game had quads
paying 27 for 1, then this game should be about break-even. That is
to say, with quads paying 40 for 1, or an extra 15 for 1 (15 is the
difference between 40 and 25), the ev increases by about 3.54% on a
linear approximation basis. One way to look at it is taking the
base 99.54% game and adding 3.54% to get 103.08% as an
approximation -- recall the quads final got hit at 45 for 1!!!
Clearly, to get the max ev, one has to optimize the strategy. I
like chasing quad progressives because it's faster to hit than a
royal flush.
May your quads be fat and quickly hit!