Too early to say which team will win a title first, IMO.
That said, I think Boston is far and away better set-up from it's rebuild than LA is in just about every category. When it comes to organization/front office were light years ahead of them. We have one of of the best young coaches around in Stevens, they have Byron friggen Scott. We have a much better young team with a larger collection of good young players than they do. We have a lot more in the way of "tradeable assets" on our roster in the likes of young prospects, vets on expiring/non-guaranteed deals and a plethora of draft picks in multiple years. LAL has to give it's pick to Philly this year while we could realistically go into the 2016 draft with a top 5-7 pick, a top 8-12 pick and another top 20 pick.
LA will always be a talked-about FA destination and who knows, maybe the end up signing someone major in the next couple years but I'm just not sure NBA players look at the current state of the Lakers FO/Ownership or their current collection of non-Kobe talent and say "Yeah, I wanna go play there". They sure haven't in the last couple years at least. I understand were not exactly a prime FA target ourselves, but there's a lot of truth to all the talk about Stevens being highly regarded in player circles and if this team improves to a 46/47 win 5th seed and makes the 2nd round, that conversation may change a bit.
Even if you go on "high-end talent" alone, the one thing every Negative Nancy on CB will point out, do they really have much of that anyway? Russell hasn't exactly set the world on fire so far (of course, it's super early) but we know very little about how good he's gonna be. Same with Randle, and I've always felt like Randle has too many limitations to be a star. Personally, I think it's quite possible we have the better guard prospect in Smart and a far better collection of young talent when you include Sullinger, Olynyk, Rozier, Hunter, Mickey and Young. Plus we'll have multiple good-decent 1sts coming next year.
Even if I wasn't a die-hard C's fan, I would be saying that Boston has done a much better job with their rebuild so far.