I used to play Shatranj a lot when I was a teenager with a friend of mine
and also with my father.  We all enjoyed it.  It has its own unique feel.

Some modern chess players who have tried it have told me they didn't
like
it.  That is their right but I have gathered that often their dislike is
due to conservatism: they simply feel uncomfortable trying new things. 
Some also make the mistake of using modern chess as the yardstick and in
so doing see Shatranj's slower pieces as thus being weaker and so less
enjoyable (less power).  They miss the point, I think.  A slower game is
NOT an inferior game just a different game.  Draughts (checkers) is
another game with slow pieces (and in some varieties the Kings are also
slow) but millions enjoy it nonetheless.

When I first played Shatranj I realised that I had to divest myself of
much that I held to be true in modern chess: pawns, for example, are much
more powerful than in the modern game, yet paradoxically promotion is
less
important.  This tended to make me use the pawns more in the game and not
worry so much about preserving them in order to promote them to Queens. 
The play of the Shatranj Queen and Bishop are also correspondingly
diferent.  The Bishop is useful mainly as an annoyance, a covering force
against rook attacks, and, in conjunction with two friendly pawns in a
chain formation, as a barrier and fortress.  Thus a pawn on e3, another
on
d4 and a bishop on c5 mutually support each other and can be difficult
thus
to break up without the use of rival pawns.  This arrangement is good in
the middle game when enemy pawns have advanced forward and have moved to
where such a formation can no longer be threatened.  As for the Queen,
its
limited power could either be used defensively to shelter the King
against
Rook checks, as H.J.R.Murray noted the European players were prone to do,
or used aggressively by moving it forward, often in conjunction with the
King's Bishop, to assault the enmy lines, as the Arab masters used to
do.
 After a Bishop sacrifice taking out a few enemy pawns, the Queen, alone
or
in conjunction with say a Knight, can gain entry into the ranks of the
enemy and prove a real threat.  The reason: because enemy Bishops and the
enemy Queen cannot usually attack it (unless the enemy Queen is a
promoted
pawn on the same set of 32 squares, and the enemy player is often forced
to
use a Rook or Knight, or bring over his/her King thus exposing the King
to
attack.  Thus the Queen ties up enemy forces much more powerful.

Likewise with the changed power of the Queens and Bishops the Rooks and
Knights come into their power.  Not having to fear Bishops, or Queens
sweeping down the board at them, Rooks are the most powerful pieces, and
once a Rook can break into the enemy ranks can usually cause havoc,
especially if both Rooks can get in.  Knights also find themselves more
influential, not having to fear being swapped off by Bishops so much, and
can really threaten the enemy with forks and checks.  The net result is
often an interesting middle of the board clash.

Where the game disappointed some people (and led to the changes made to
bring in the modern game) is the length of time it takes to play.  I've
had many games that went over a hundred moves, easily.  Plus the end game
is less decisive without Rooks, and as a result can be a long drawn out
affair.  The rules of Shatranj allow for a win by Bare King.  This is OK
but no doubt left some players less than satisfied as cornering the King
is supposed to be the prime object of attention, so I can understand why
it frustrated some people, but I still like the game.  Strategy, tactics
and feel are really different.  If one is a little jaded with modern
chess
it can make an interesting alternative for a while as a break.