Pros
It has a decent environment for research activities with many renowned scientists (both present and past) to draw inspiration from. UCLA has a high ranking in many world indexes, making it a great addition to your CV/resume. The University offers career development opportunities (workshops, seminars). But the practical use of such may be limited and these need to be sought out by the individuals on a proactive note.
Cons
University on a whole and certainly the department I work in seem to depend a lot on legacy than moving ahead with new technologies and software. Most employees are set on their old ways and resistant to any change. Lot of bureaucratic challenges to go thorough if you need something (for research) outside the box they live in. Travelling to and from the University is a nightmare due to the LA traffic. Living close (20-30 min walk) to the University at a 42K annual postdoc salary is almost impossible, since a small apartment would cost 1500-1700 USD monthly. Tried living close to the University for one year to maximize research efficiency and ended up in credit card debt. There is a postdoctoral Union that serves very little purpose, other than individuals getting credentials for CVs. By default, each postdoc *has* to pay a percentage of their salary to this union (some 30-50 USD monthly). Each year they do something with the University called negotiations and each year its the same outcome. University declares they will reduce postdoctoral benefits, cut down leave days, make the postdocs sign in and out when they arrive/leave, reduce salaries etc. The union then backs down to keeping what we already have; Nothing much. The University would throw a bone to the union like offering daycare or something at times. Overall, nothing good happens. What UCLA offers are the NIH declared lowest possible salary for the postdocs. No compensation for the higher living costs in LA. Do not have the illusion that things will get better each year if a person in one of these postdoc unions approach you. UCLA is set in its ways for all eternity. The University has no decent night time transportation system to get around the campus and to even some of the University owned apartments. This is a major safety problem since walking the streets of LA at night (even near the campus itself) does not feel secure (with many homeless people about, and significantly deleted police forces). The campus is quite dimly lit at night making these concerns even more real. University owned apartments are of a lower cost, but there are long wait lists and the apartments are well away from the campus. It is at least a 30 min bus ride each way, or you need to purchase a parking permit at ~ $230/3 months. As a postdoctoral scholar, the living challenges to face (some described above) everyday has kept me from studying science as I should be doing at this stage of my career. UCLA is a decent place to do undergraduate or graduate studies. Based on my personal experience, I do not recommend UCLA for a postdoctoral training, due to the lack of support from the University to postdoctoral scholars (in many ways).