Anyway, I tried making a more in-depth approach to testing the power banks by using my digital charger (which can use USB as a power source) and charging my phone at the same time, kind of like a stress test of sorts:
Normally the charger can use up to 1 amp per battery (with 2 batteries like above) but if the source is unable to provide enough amps, the charger will try to make do with what's available. In this case, if both ports are used, the Pineng can supply 1.4 amps on the 2.1 amp slot and the Romoss can provide 1.2 to 1.4 amps (it seems to fluctuate depending on available power, the lower the available charge the lower max amp provided) on the same 2.1 amp slot.
Granted, the difference between the two is partly age and battery technology (the Romoss is an older model but just a month old and uses Lithium Ion Batteries, vs the newer model Pineng with a Lithium Polymer battery) but you can see that there is a marked difference in performance when both slots are used. On the other hand, if only one slot is used, they both provide at least 2.0 amperes (my charger can only utilize 1 amp per channel at max of 2 channels so I cant say for sure if they are pumping 2.1 or just 2) but it might be safe to assume that it would provide that amperage as advertised.
So between the above two, it's almost a no brainer on what to choose (if I was asked on what's better) since the Pineng is cheaper (specially if you can get it on a Lazada sale) with newer technology for safety and battery, it's less bulky and lighter than the Romoss.
Take note though that the Romoss Sense 6P is now available on Lazada and is sporting the same LED/LCD percentage screen with the same Lithium Polymer battery as the Pineng, so they might turn out as even in terms of performance (or maybe slightly better for the Romoss) but on a sale day, Pineng is really cheaper.
With that out of the way, I find myself pretty lazy of late that I barely make my favorite Vietnamese coffee and just use instant coffee to start my day, and it's not really providing me with enough zing to do my thing. I'm guessing that the Vietnamese coffee has a lot more caffeine than the instant one which makes me less than powered up (yeah, excuses hahaha) but I'll see of my little experiment with the power banks will apply to me, I'll strive to make iced Vietnamese coffee tomorrow :)