History Lover has summed it up nicely. I would only add that, although most of the freebies and bargains probably are self-published unknowns, I've picked up a number of them that have actually been quite good reads. And sometimes 'name' author books go on sale too . . . for example, they recently ran a special on James Bond books by Ian Fleming.
As to the cons listed. . . . . as she notes, they're mostly fairly minor, though I suppose some things could be more important for you.
I rarely loaned books anyway as there aren't that many in my circle who read as much as I do or the same sorts of things when they do. So even that one isn't a major issue to me.
As for images and charts, I find that they look better on one of my tablets or my computer -- because of the color screen . . . . If I think I'm going to want to refer to the chart/map often, I'll put the book there and mark the relevant page, so that whenever I want to refer to it I can open the kindle app and check it quickly. So that, at least, is a good work around for me.
Also, I find the 'time to end of chapter' to be fairly accurate and it works for me. On the kindles with a progress bar instead, it will have marks showing where chapters are which gives some idea of how close you are to a 'stopping place', but it's still not quite as clear as in a paper book where you can quickly flip pages.
I think the big thing most people have to adjust to is the use of locations rather than pages. . . .it does take a bit to get used to how long a book is, for instance, when you're using locations rather than pages. Fortunately, most books are also still published in paper, so the kindle file has a number of pages notation as well. I've gotten quite comfortable with just having my percentage complete and only really use the page count to judge how 'fat' a book it is in the first place.
Regarding covers -- the 'feel' of a good quality cover can be simulated pretty well with a good quality kindle cover. Though to really see the cover image in all its glory, you need to have a color screen device. I do remember looking at covers, especially when I've gotten halfway through a book, and trying to work out if the image really is representative.

And I have a few paper books even now that have really great covers. But, as HL says, a minor issue.
I do still have, as well, some really nice bookmarks given to me over the years. . . . one of these days I'll do something clever with them. . . . but mostly I used bookmarks that were paper and they tended to have a 'shelf life', if you'll pardon the pun.

So, yeah, a minor issue.
I have talked to one or two actual people who tried kindle and then gave up on it and went back to paper. Mostly, their arguments were that they found the tactile experience of a book was way more important for them. So that's a personal thing.
OR, they couldn't find the type of books they read available on Kindle. This was in the early days and many many more books are available now, though.
OR, they found that they didn't really read any more than the had done, so didn't feel the expense was worth it so they sold it and went back to paper. (That's a bit mitigated now, since there is a relatively inexpensive ($69) basic model -- initially they ran close to $400 so probably not something for someone who only reads a book or two a year.)
And at least one person mostly reads stuff that isn't ideally suited to kindle -- things of a technical nature with
lots of pictures or charts and better suited to a larger page.
Oh, and I have one friend who is a graphic artist -- book covers are a really important part of the experience for her. But, even she, who generally prefers paper books, has gotten a kindle for when she travels.
There's also at least one person who tried kindle early on, gave up (sold it) for one or more of the above reasons, and later bought another one.
The great thing is, Amazon has a generous return policy, so you can try one out for a month and return it if it doesn't work for you -- all you pay is return shipping.
ALSO: don't let people tell you you HAVE to buy books from Amazon and can't read anything from anywhere else. That's just not true. As long as the book is in an appropriate format, or has no copy protection and can be legitimately converted to an appropriate format, it can be loaded on the kindle.
What IS true is that Amazon, like Barnes and Noble with the Nook, have copy protection on most books -- as a requirement of most major publishers -- and books purchased from one store won't work on the devices for the other store. Removing that 'digital rights management (DRM)' is against their terms of service but, really, there's probably not much available via B&N that you can't find on Amazon anyway. To that extent, you are 'locked' into Amazon's store. . .but there are lots of
other places that have books with NO DRM which can be purchased and converted if needed.