Well you can put me into the camp of I like rolling for stats. I don't see that high mods make a big difference. I think that a good DM will use CRs as a guideline, and smart players should even with low scores (except spell casting mods) usually be able to beat CRs that are 1-3 points above them. I played a FANTASTIC campaign where the DM was like "we are all mature, just pick whatever stats you want, if you go uber twink you get standard array" and it worked fantastically. I think that Point buy makes playing some classes almost impossible. Monk is a great example. You have to roll well, then you can play monk, but a fighter needs 2 good stats, a wizard (arguably) needs 1, a Monk or a Bard really need 4. Also many would argue that the monk or bard are not the best choices for classes anyway. So Point Buy punishes those that want to try a good role-playing experience by further hampering the "fantastically flavorful" bard.
In our current campaign we rolled stats and it is working out great. The players are smart however and some encounters are scary for the players (5 4th level characters Vs. 12 hobgoblins (6 with ranged weapons, 6 with melee)) and some are awesome because of smart players.
One of the latest encounters in the campaign was vs. 4 mounted human fighters (2) with 1 mounted fighter leader (4.) We finished that encounter with only our scout being wounded (he rushed ahead and got hit by a horse) and none of the fighters being wounded (thanks to pyrotechnics smoke cloud that got 3 of the horses and riders, a hold person on a rider, and a shatter on a military saddle) The DM was like WOW that was supposed to be a 5-6 round combat that lasted 2 fast rounds and no one was wounded. We captured the leader, and let the others go. I tell this story to illustrate it didn't matter WHAT our stats where (as long as we could cast the spells) we won because we used what resources we had and were Smert about it.
I am upset by the "balance" talk at the table. I think that people get hung up on the "balance" issue WAY too much. You say, "I know my players won't be pleased" Well that should be a red flag. I think that the players should have as much say in the determining of stats as the DM. They can make their characters and use one of the MANY online die rolling tools to e-mail you the results (that way they get 1 shot and they can't tamper with the results) Or they can make their characters and leave off the stat bonuses on their sheets (that is what our new player did), when they get their in 15 minutes they will be ready to play. Your options are limitless really. I just think that the standard 28-point method is played out, and limits options for the players. Even the D10 system allows for customizing the "standard array."
At level 3 try putting them Vs. CR 5s and see how things work out (regardless of their stats) The object of the game is to have fun. If you honestly think that the players won't be happy about their stats then do you expect them to be happy with the game in general. I have a new philosophy when it comes to games as well. If you want long-term games the players need to love their characters, and the setting. The adventures can be good/bad, but the general location and characters stay. I would rethink a stat choice that would upset the players.
