They are a good option but I'll add two important side notes:
1. Their interconnects with overseas telcos is not the broadest, so you may find 2-way SMS does not work. This
link has more detail.
2. Their data pricing is very expensive right now (50c/mByte), and at the moment they only offer 2G EDGE services. 3G is not too far away (inbound roamers can already use it).