I have only played 14 games so far (4 veteran level, 10 on All-Star) so
I am sure I am missing some nuances and yet to be seen glitches in the
A.I.

Graphics:
The stadiums are not quite as good graphically as TP99 but they are
accurately represented.  The player graphics are pretty good up close,
but from a distance are not too great.  The only gripe I have with the
players up close is that they do not vary in size too much.  The really
nice touch as far as graphics are concerned is the player animations.
The homeplate collisions are great and can cost a run or two if the ball
is knocked out of the glove.  The infileders have nice throwing motions
on the run and the 1st baseman stretches way out on close plays.  The
outfielder animations include homerun robberies, diving catches,
barehanded catches, etc...  The signature stances and pitching
deliveries are plentiful. The camera angles are good and switch and zoom
appropriately.  Finally, the opening FMV sequence sucks.  It seems like
the developers could find more exciting plays and music than this.

Sound:
Sony did a real good job with the sound in MLB 99.  Vin Scully does a
credible job (even though it doesn't measure up to the two man booth in
TP99), the on-field effects are clear and well done, and the organ music
adds to the game.  The background "nachos!", whistles, etc... are good,
but like most games, get a bit repetitive.

Control:
The control is really good.  Hitting is responsive, fielders move like
they should with no delay, and pitching is really not an issue when it
come to control.  The Total Control Batting is what has really impressed
me with MLB 99.  Sony has kept the cursor system but added the feature
of optionally guessing at pitch location and pitch type.  If you guess
right then you get a sweet spot and a lock-in on the ball.  If you guess
wrong then your cursor becomes smaller.  If you choose not to use this
option then your cursor stays the same and no advantage or disadvantage
is gained.  This is much the same system as used in WS98 for the Saturn
and a bit like the fat pitch feature in Konami's Bottom of the 9th.
Additionally, even if you guess right and get the lock in on the ball it
doesn't mean you get an automatic double or homerun.  In fact, many
times it results in nothing more than a flyout.

The Total Control Fielding is also an interesting concept.  By pressing
the L2 button you can execute more spectacular plays in the field when
you need them. So far I have barehanded one ball and robbed Junior of a
homerun in right field at Fenway.

The pitching is not as impressive.  Just choose a pitch and then a
location and press x to pitch.  I haven't been able to throw a wild
pitch yet.  In fact, I tried throwing as far out of the strikezone as
possible and batters are still getting hits on occassion.  I assume
there are no passed balls either.  You can occasionally hit a batter,
but not every time you try.

Gameplay:

The most important factor to me is gameplay.  MLB 99 delivers in this
area.  The game plays very smoothly and quickly.  No long load times
when making changes and, I know some people like this, no crap like
warm-up pitches before the game and for relievers once they enter the
game ( I would have liked to seen a warm up the bullpen option though).
There are plenty of extra base hits and in a good ratio.  Steals are not
too easy and not too hard.  Homeruns are also hit at a realistic ratio.
The variety of hits is good--choppers, slow rollers, down the line
shots, gappers, etc.  Something Sony didn't change enough from last year
is the tiring of pitchers.  Pitchers still have too much stamina but not
as much as in MLB 98.  The main gripe I have with the gameplay is the
large number of throws over to the base when a runner is on.  Example,
Mo Vaughn was on 3rd and Jefferson was on 2nd.  Randy Johnson threw to
3rd three times against a small leadoff--What the hell? Another gripe
with the AI deals with baserunning.  The cpu makes dumb decisions from
time to time in trying to take an extra base when it is obvious the
runner will be thrown out.  The baserunning as a whole is pretty good
but is far from perfect.  I am sure there are other AI issues that I
haven't encountered, but overall it is a solid AI.

Interface/Stats/etc...:

Switching from screen to screen is fast.  The menu layouts are excellent
and easy to read and interpret.  There are a lot of options and
different settings, including different season lengths (Thank
goodness).  I am impressed with the number of stats kept.  There are
stats galore as well as hit charts for each player.  The stat leader
screen is nice.  A photo of the player and his stats are shown for each
stat category leader screen.  I haven't seen any stat screw ups so far
during a saved season.

MLB 99 features a Spring Training Mode in which 2-6 games can be
played.  Players can gain attribute points during the pre-season to be
applied to the regular season.  This is cool for created players.  If
your minor leaguu player can't hack it in Spring Training then he will
not even make it on the roster.  Even if he does make it on the roster
he needs to keep up a minimal performance during the season to keep his
spot.  Otherwise, he will be sent back down to the minors and replaced
by the original player occupying that spot.

The major player awards are given at the end of the season.  I simmed a
full season and the awards were very realistic as well as their final
stats.  There is even a rookie of the year award so that a created minor
leaguer can win an award.

The create player is great.  It is fully configurable even down to the
type of stance you want to use.

Other features I like are:  a division realignment option where you can
customize divisions, user records are kept, and the homerun derby is
pretty good.

Overall:

So far I really like this game.  It is not as flashy as TP 99 in
presentation but the gameplay is much more solid.  It plays much more
like real baseball than TP 99. Also, it it has an impressive aray of
stats and options.  In many ways it is obvious that Sony borrowed from
EA and other games in the development of MLB 99.  Although far from
perfect it is easily the best baseball game on the psx.  It is nice to
see that Sony focused more time on gameplay than flash this year.