Need help to decide Mysql vs Postgres

Hi all,

From whatever reading and surfing I have done, I have found that postgres is
good. Actually I myself am a fan of postgres as compared to mysql. However I
want to have some frank opinions before I decide something.  Following are
some of the aspects of my schema, and our concerns --

- We have around 150 tables on the DB
- We have lot of foreign keys between the tables
- Couple of tables are going to have around couple of hundereds of millions
of records (300 Million right now and would grow). Few of this tables are
fairly wide with around 32 columns, and have around 3-4 columns which are
foreign keys and refer to other tables
- Most of the DB usage is Selects. We would have some inserts but that would
be like a nightly or a monthly process


Our only concern with going with postgres is speed. I haven't done a speed
test yet so I can't speak. But the major concern is that the selects and
inserts are going to be much much slower on postgres than on mysql. I dont
know how true this is. I know this is a postgres forum so everyone will say
postgres is better but I am just looking for some help and advise I guess
!!!

I am not trying to start a mysql vs postgres war so please dont
misunderstand me .... I tried to look around for mysql vs postgres articles,
but most of them said mysql is better in speed. However those articles were
very old so I dont know about recent stage. Please comment !!!

Thanks,
Amit