-No caller ID for text messaging. You have to open a txt to see who it is from. (someone correct me if this is phone limitation and not a network limitation).
-Limit of 160chars for text messages. Although this limit exists on Vodafone as well, most 021 phones allow you to keep typing past the 160 limit. Besides having the ability to send long txt messages in a practical way, this also allows you to easily write your full message in one go, and then go back and edit it down to under 160 chars, instead of having to go back and edit as soon as you hit the char limit. This can get very annoying, especially for someone like myself who often nears 1 or 2 chars from the limit.
-Low battery life when compared to most GSM phones. This seems to be one of those things that's known but not really talked about. I didn't know about it until I had already made the switch. But many 027 phones seem to have as little as half the stand-by life when compared to their GSM counterparts. I bought a Nokia 3205 and it was quite annoying to learn that Vodafone's 3200 equivalent enjoys a significantly higher talk-time and stand-by time. I was using a two-year-old old Sony T300 on Vodafone, not known for exceptional battery life, and it was quite disappointing to learn that I was actually "downgrading" from that.
-Inability to check balance by txt message. "bal" to 777 is a very convenient way to check your balance when in noisy / social situations, or when you don't want to drain precious battery life from your short-lived 027.
-Inability to top-up by txt message. Again, it's just more convenient and also more practical in noisier situations.
Perhaps, with voice/data, 027 offers benefits that Vodafone does not. I don't know. But, as a texter, I think that the $10/month pricing is counterbalanced by the lack of some practical features and poor battery life.