Well, having been trialled in the three SuperSeries matches, there's now a small body of evidence with which to form an opinion on the expanded use of technology. My view is that it was a resounding success and should stay. For instance, with Martyn's innings today, the technology was used twice in relation to LBW appeals. In the first instance, the side-on replay indicated that the ball was indeed going over the stumps - a replay that the on-field umpire would not otherwise have had access to.
The second instance, was when Umpire Dar wanted to know whether Martyn had got an inside edge onto the ball, and whether the ball had pitched in line with the stumps. Again, the replay resolved these issues, and Martyn was given out LBW. In both cases, the replays resolved the doubts that the umpires had, and were quite unambiguous. The technology assisted the umpires to arrive at the correct decision.
Of course, the major complaint going into the series was that the technology - or the referrals to it - would be too time consuming. However, in Australia's innings, despite four referrals, the innings finished on time. Besides, who cares if a few extra minutes are taken up? I mean, spectators - when bowlers go around the wicket - wait while the sidescreen is moved and the batsman scratches out a new guard.
They also wait for while video run-out decisions are being made, and while captains have endless conferences with their vice-captains, keeper and bowlers about field placings/tactics. So, what opponents of technology are saying, is that we can afford those delays, but we can't afford the very insignificant delays (as shown today) in order to help the umpire gather more evidence to hopefully arrive at the correct decision. Crazy stuff.
Anyway, let's hope that the technology stays. As shown in this series, it is not often sought, but when it is, it often adds to the adjudicative armoury of the umpire, and improves the quality of decision making. Furthermore, the time-wastage fears are very much, as shown today, over-stated.