We need to make our description a bit more precise - and we're working on comparisons. In terms of pure RAM usage (as opposed to ROM) in our experience the display resolution contributes a lot to what's left (unless there are dedicated frame buffers). So if you mention <= 64kb RAM, what kind of displays are you typically dealing with?

Generally I think we're aiming a little above LVGL/uGFX in terms of configuration, but also with with a much richer UI / features.