If I were you, I would definitely wait with a decision.

As pointed out Mt. Gox is quite a fail when it comes to withdrawals, which is basically unacceptable. Not sure if those withdrawal issues only affect fiat or also Bitcoin withdrawals. I think if your plan is to buy and hold and there are no issues when it comes to coin withdrawals at Gox, then you can go for it. If you plan to get fiat out again in the near future, you obviously should look somewhere else.

However, Bitstamp is currently also going down the drain. Massive lags for 24 hours, deposits are not being credited to accounts since last week although they've reached their bank and since these issues emerged there was just one vague statement from them on Monday, complete silence from that point onwards though shit got worse and worse.

So yea, I think both exchanges are having severe issues and wouldn't really recommend either of them, that's the sad truth.

Edit: The minute I wrote this, Stampman decided to give a life sign, stating the deposit issue has been resolved (https://bitcointalk.org/index.php?topic=38711.msg3652288#msg3652288). Can't confirm yet because I'm still waiting for my tranfers from last week. I'll update if that changes.