San Diego for sure... the weather, the air, the traffic...
The only thing LA has going for it is the culture and the general friendliness of the people... or if you're in the entertainment biz, which I have been.
SD is the nicer city to reside in without question.
From a hobbying perspective, SD appears rather limited.
I have been in most parts of the world, and San Diego is clearly one of the most visually beautiful cities anywhere. LA is not. In fact, it is not even a real "city" compared to major cities around the world. Just a sprawling, traffic snarled mess with large, gang infested ghettos, separate rich folks enclaves, and no significant downtown to speak of. In general I have not found people friendly there as someone mentioned above. Certainly not as friendly as those I've been in contact with in SD. People seem happier to be living here, and that shows in their personalities and amicable natures.
As for culture, SD also has plenty to offer at venues easier to get to than those in LA. We have live theater, opera, symphony, numerous clubs, concerts by popular artists, excellent restaurants at scenic locations, and the museums/activities/and grounds of Balboa Park. And for outdoor recreation, well again no contest when you consider all that is here and more accessible than in LA.
As for hobbying, well just look at the price differential of the ladies in both cities. I'm perfectly content with the local and visiting providers available in "America's Finest City."
San Diego better by far as far as I'm concerned
+10 @Cobra1 
I've resided in Laurel Canyon, as well as in Sherman Oaks, Studio City, and Burbank in LA
for work purposes {outside of Providing}.
Although those places had their charm, all of the negatives that you, @Cobra1 have
professed is indeed all true. Not to mention,
the smog, and just the general feeling of being a miniscule minnow in a sea of big sharks...
literally and figuratively! {especially within the Hollywood Industry}
I travel worldwide, and am always feeling very blessed and content to finally return home to
The Finest City -- Te amo San Diego!
Totally agree with you. You mentioned every single detail... I don't know about others. This is Home to me. Love this "America's Finest City."
Hehehe...
Still Love driving up to LA, for the gents that can't get down here. They don't live in LA. They are schedule for work. 
Posted By: cobraa1
I have been in most parts of the world, and San Diego is clearly one of the most visually beautiful cities anywhere. LA is not. In fact, it is not even a real "city" compared to major cities around the world. Just a sprawling, traffic snarled mess with large, gang infested ghettos, separate rich folks enclaves, and no significant downtown to speak of. In general I have not found people friendly there as someone mentioned above. Certainly not as friendly as those I've been in contact with in SD. People seem happier to be living here, and that shows in their personalities and amicable natures.
As for culture, SD also has plenty to offer at venues easier to get to than those in LA. We have live theater, opera, symphony, numerous clubs, concerts by popular artists, excellent restaurants at scenic locations, and the museums/activities/and grounds of Balboa Park. And for outdoor recreation, well again no contest when you consider all that is here and more accessible than in LA.
As for hobbying, well just look at the price differential of the ladies in both cities. I'm perfectly content with the local and visiting providers available in "America's Finest City."
San Diego better by far as far as I'm concerned.
The obvious answer is San Diego for countless reasons.
But I may be biased heehee
I've lived in SD for 36 years and have spent zero nights in LA so I may not be qualified but IMO LA is one big developed sprawl from orange county all the way to ventura. Great beaches but way too many people in LA.
There are many great things about BOTH cities! I like to find the beauty in everything and if you know where to go in LA (and where not to go, it's a very awesome city)! San Diego is def one my favorite places to visit especially the beach areas. Can compared to OC, I feel like SD is way better in that regard! 
Hahahhaa ok, let's compare the two and start a new thread based on the comparisons
Why?
Del Mar, Point Loma, Sunset Cliffs, OB, La Lolla, Mt. Laguna, Cuyamaca, Gas Lamp, on and on and on...
Discovered by the Germans in 1904, they named it San Diego, which of course in German means a whale's vagina.
The downers.. Chargers....Padres....clippers...
Why do we always name sexual things after animals is my question 😂😂
Nvm that's from Anchorman lol
I've done some time in LA. Not like, hard time, like, I lived there for awhile. SD is by far nicer, not as much on it's own larels, but more because LA has a number of bad qualities that SD just doesn't have.
The LA traffic is easily 10x worse, everything is always dirty without exception. SD people are a little aloof but mostly nice, LA people are usually a little less kind in general. LA is hotter in the summer, rains more in the winter.
"They call Los Angeles the "City Of Angels." I didn't find it to be that, exactly. But I'll allow there are some nice folks there."
