I'd go for the Pentax because not only does it have a bigger sensor for better low-light capabilities during gatherings (where you might not have lots of light), it has a HD video function which you can use.
it will be better for u if you know what are the strengths and weaknesses of each system offering. every camera will enable to shoot good pics as long as u know what u r doing and do them under the correct situations.
Kr is a very good camera at its price point.
Good low light performance both from the APS-C sized sensor and good engineering.
Many good on camera features like HDR, shake reduction, preview of white balance and color selections, dual battery compatability.
I have the e620 and I like using it. But if I were to choose all over again at this point, I might go for the pentax k-r. Reason being the e620 is a soon-to-be-2-years-old technology, so naturally if you're going for all the latest improvements, you won't find it in the e620.
slightly larger APS-C sensor giving more usable high ISO pics
AF assist lamp
li-ion and AA compatible (once the battery adaptor is out)
Weight with kit lens and li-ion battery should be similar for both, and both have in-body image stablization, shake/dust reduction. Price point should be similar as well, although the e620, being an older model, ought to be somewhat cheaper. Of course, if you intend to upgrade to their flagship models then lens choices would be an important factor as well.
Have you tried both cameras? The e620 has a somewhat different style of grip that some can't get used to. Ultimately it's your choice, since you might or might not care for all the additional new features. But if you're still interested in what 4/3 has to offer, why not look at the mirrorless offerings from Olympus and Panasonic?
*edit* note about the high ISO point. I used to complain like crazy about the high ISO output of my e-620 (when viewed from the monitor). But after printing in 4R, I realized it's not as big an issue as I thought, and so I'm a happy Oly user once again.
You yourself say you are a newbie. You say you narrowed the 2 kits, but did not mention what aspects of the 2 you were uncertain of. Therefore it is logical that you did not do a thorough comparison yet as you could not specify which aspect of the 2 you are uncertain of.
You say you want to do "mainly family gatherings/ functions and some streets" which is a clear newbie statement as anyone who did even basic research would know that any camera will do a good job in those aspects. This is also explained in the FAQ you so deride.
Just because the FAQ did not cover every single possible combination of "A vs B" cameras out there to spoonfeed you, and instead gave logical, real-life advice that would help you make your own informed decision as an adult, does not make it "not helpful at all". It is only "not helpful" to people who expect spoonfeeding.
Have I ever? Oh yes... many times, especially when the k-r was released. I even put my e620 up for sale at one point but thankfully convinced myself otherwise and saved my wallet some hurt.
Anyways as daniel-sg mentioned, the e-620 is kinda old. Not that you can't choose it if you decide that's what you want but if you're going to consider 4/3, I think it's better to look among the mirrorless offerings. That's where the development focus is on currently.