I have a Libra 2 for personal reading and an Elipsa 2E for journals. A couple of minor nits like you mentioned aside, I love them. They can read almost any format I throw at them, I can fetch books directly from my library, and if I add an article to Pocket on my laptop then it shows up on my Kobo next time I pick it up.

I also read way more now that I've gotten the Libra, largely because it's so light and ergonomic for laying in bed at night and flipping pages. I added a popsocket to the back for easier 1-hand holding.

The Elipsa is better for reading large content like Communications of the ACM or similar, where the Libra was simply too small to be readable. I hardly use the pen for either highlighting or notes, but it's there if I want it.

If/when either of those die, I'll look at the color versions as potential replacements. It highly depends on how much of an effect the lower resolution has on readability. If it's less pleasant to read at night, or if PDF journal articles are a little fuzzier, I'd rather stick with B/W. If the only downside is that the screen is a bit darker so I have to turn the backlight up, then only get 2 weeks between charging instead of 4, I might consider it.