Excuse the cynical POV here, but it's from a number of years of dealing with such things. The problems I find with enterprise software as a rule are it solves the above but fails at:

1) Realistic scaling. Just about every piece of enterprise grade software I've seen falls off a cliff when it hits a certain load point. This is ALWAYS enough to sell it to you. When it goes wrong...

2) When it goes wrong, it's a nightmare of maintenance contracts, verification, finger pointing and telephone calls that last hours.

3) It rarely works as advertised. I mean literally 1% works as advertised.

4) Trials and realistic evaluations without crazy constraints are not usually possible (this is changing slowly).

5) Installation is a breeze but when it comes to backup/restore and upgrade, it's a pain in the butt.

Time is money. The difference between "enterprise level software" and "OSS" platforms are the following:

* OSS time is spent up front.

* Enterprise time is spent later on and costs more up front.

I'd rather have one Ninja on the team and lose the enterprise software. Ninjas scale better as well.