I'll just share my experience here.

My first 2 cards were UOB Lady's Card and UOB One Card which I applied for at Tesco Puchong.

Then, UOB called me few times to offer other cards to try out for free, so I got another 2 cards- UOB Preferred Platinum and UOB Vox. As I am their "Preferred Customer", the annual fee for Preferred Platinum are waived for 2 years.

After using these cards for 6 months-1 year, I found that:
UOB Lady's Card is good for frequent grocery shopping.
UOB One Card is good for general cashback.
UOB Preferred Platinum is good for people who travel a lot.
UOB Vox is good for online shopping.

I'm thinking of cancelling UOB Preferred Platinum & UOB Lady's Card as the annual fee is RM200+ and RM70+ respectively.

One Card is good enough for daily use (I use it to pump BHP petrol) while UOB Vox is my favourite card as I shop online frequently and its rebate of 0.3% is higher than One Card so I use it to swipe more often than ONE Card.

The best thing about UOB Vox is the card holder can convert a single transaction >RM1000 to 6 months of installment with 1% upfront interest. That's better than other Easy Payment Plans.

Regarding cashback, from my statements I notice that cashback is 2 months later after transaction month for UOB Vox and UOB Lady's. For UOB One, it's on monthly basis.

So far, UOB staff and CS have been quite helpful and I could reach them easily, unlike some other banks... their lines are forever engaged and CS is always "still busy".

Oh yes, as for paying utilities and insurance, Maybank Amex is better. Instead of getting rebates, you can earn vouchers with higher value.

Wait, I thought they just revised it last year? 400 points =RM1. Maybe they'll revise other things this time.
Last year alone I earned RM400+ vouchers from MBB.