An Ortofon Cadenza Red is a nice and detailed cart for under that money, and
it's kind of between low and mid output MC range, to where your 99 w/ its
tube phono stage can probably stretch it -- I believe that tube stage has a
tube-sub option (e.g. 12AU7 => 12AT7) to raise its gain, which when
combined with the line-stage's very high 23dB gain should be sufficient for
the Cadenza. You definitely don't want to go to super-low MC (0.3mV or
lower) without a dedicated MC phono stage, though.
Another good option down the road is to upgrade to a Rogue Ares phono
(more detailed than the 99's stage for sure, and even better if/when the stock
SUT is upgraded), and then to upgrade the line-stage with an Athena (big
jump up from a 99, sonically). You could also get your 99 super-magnum'd
by Rogue (beyond the magnum status) if you don't want to go too far &
expensive on the preamp upgrades just yet.
I'd also stick with the Scoutmaster; great table if you're OK with the arm.
