Its just a personal opinion and 4GB extra is a step in the right direction, but even that 4GB won't go far, if you are doing the type of streaming / tethering which justifies the premium which 4G attracts from the networks currently offering it.
At the end of the day, with feet planted firmly into reality, its only a good deal and worth the additional expense if you can use it and to your advantage, and for most mobile data users, it simply won't fall into that category. The investment will never pay for itself.
For those who would fully utilise and therefore get the benefit of the faster technology, the current data allowances don't allow for the 30gb, 50gb or 150gb which they are currently consuming on All-you-can eat. So you get one type of customer who is overpaying for something they are not getting the benefit of (and never will), and others who would use it at its full capability, but can't, because of the 3G-style data caps.
I know somebody who has recently upgraded to 4G and who uses less than 1gb a month and think "what is the point?", the few lines of text that they frequently enter into facebook thirty times per day doesn't seem to appear any faster on their 4G than on my 3G connection and it still appears in the time it takes a human to blink on either connection, but they are paying three times more per month for little practical reason other than because their mates have it, or because their phone happens to have the compatibility so they feel compelled to get a matching network (even though their personal data usage doesn't go anywhere close to ever justify it)
Unfortunately, when that novelty wears off, they still have 23 months left to pay off the premium, whilst for much of that period, others will pay less for 4G from various other networks, and I suspect that even with 4G the usage pattern of most 'average' phone users won't change much either.
4G has its place and potential but it doesn't make much sense to me unless you are uploading 100's of hi-res photos and large files every day or steaming netflix or Iplayer all weekend.