As between no-ad and timed matches, I think the latter are more appropriate for deciding which teams advance.
Remember, in a timed match you do not flip a coin to decide who won. You give credit for sets won, and you give credit for sets where one team is leading (by two or more games, which means there was a break). It would be interesting for someone to do a study and take a look at whether the team that would be declared the winner in a time match actually would win if you played it out. I suspect that most times the leader would be the eventual winner.
Javier:
How does the time limit change the way you play?
I think it incorrect to assume that the time limit fundamentally changes the way the match is played. (I admit that this may be because I am used to timed matches and therefore am used to it and do not let it throw me).
Personally, I ignore the clock completely until there is a reason to pay attention to it. I tend not to look at my watch at all in the first set. Then I'll take a look at the set change. I will play the second set the same way I played the first if we won the first. If we lost the first, I will probably try to shorten the points and play more aggressively. But this makes sense even if there were no time limit. 'Cause if you lost the first set, you had better make some sort of change, and being more aggressive is usually a nice choice.
Anyway, I think the strongest argument is the one I made already: There is no need to tinker with 84% of matches to tinker with 16% of them. This is especially so given that those who tend to finish matches more quickly would wind up wasting perfectly good court time. In other words, assume that just 5% of 4.0 men's doubles time out. If you adopt no-ad scoring, those 4.0 players might be finishing their matches in an hour. I would think they would far prefer to be able to use the full 90 minutes and just live with the fact that 5% of their matches time out.
No ad scoring matches do not generally make the match last only one hour. Ive played plenty of them and plenty the other way and you still get to around 90 minutes.
The reason why no-ad scoring works is that for many of the games the time it takes will remain the same. What it eliminates is the chance of those super long games that go to deuce multiple times which many times are the very same ones that would cause a match to go over the 90 minute mark in the first place.
Just playing aggressively in general can mean many things. The fact that you change at all if you lose the first set and you have to do it keeping in mind that there is a time limit is bad.
If you are looking for consistantly from match to match, there is no way you can say the occasional timed match (which by your own admission only affects the match 16% of the time) is somehow more fair then no-ad scoring which would affect everyone.
16% is a lot.
And I disagree about your study, totally. You seem to have some fascination about starting out a match well, as if it's more important then ending it well. There are plenty of people (me for example) who may start out slow but I will win more than my fair share of matches if Im allowed to. Especially at 3.0 and 3.5 where players most of the time do not start out well and you spend the entire first set just figuring them out (or sometimes they are just cold and dont come alive until the 2nd set).
In our timed matches, sometimes there is a tie. (it's not a league so we allow ties) Id give way more credit to the person who was winning at the end of the match then the person who won the first set. (or even worse when you have to resort to spinning racquets, counting scores on other courts, or any other unnatural items that should have nothing to do with winning one single match)
So that's the issue again. It's not a matter of whether it's fair for one player over another, but it does change the entire nature of the game when you can actually be losing at the end of the match but you can still win because you've won a set.
And maybe your method is a bit more fairer then other methods but that's apparently another problem with the system. Every single little area that has timed matches seems to have their own way of doing it. And I think you can easily argue out a negative for every single one of them (because there really is no fair way to do it).
You may not like no-ad scoring but at least it's keeping with the usual nature of tennis which is it's not meant to be a timed sport and you have to be winning at the end of the match if you expect to win. (there is no "taking an awesome start with a smile", you need to finish)