[Quoth]

Originally Posted by pdurrant

It doesn't have a front light!

So you need a floodlight indoors.

A front-light is really hard to do on a big screen, though not impossible.

I was comparing Kobo Sage (also Elipsa), regular glossy glass LCD with budget "backlight" and NxtPaper 11 in daylight, twilight, decent ambient light, and a spotlight shining inappropriately.
Later I'll do some photos and explanations, but basically the eink only beats the Nxtpaper 11 for diffuse ambient light bright enough to read a pulp paper pocket/MM paperback. The budget LCD always loses and is unusable if any light source is reflected off the glass. Also once you need the eInk front light, the advantage of eink is lost over a good LCD, but it still beats a cheap LCD by a big margin.

It's really complicated.

1. The best is mono eink with a micro-textured finish on a plastic top layer, no touch layers and no light-pipe layer above the screen. The texture breaks down and diffuses sharper light sources. The black balls in the cells seem to be matt finish. Under macro photography the black cells look like they have copier toner or soot. The more the top layer breaks up reflections, the fuzzier the text gets. I've not seen a Kindle Voyage, but I suspect it has minimal texture on the top layer.
2. The second best is mono eink with IR touch and light-pipe for front light. The IR touch uses no layers. The layer for the front light will reduce the text sharpness.
3. Then we have capacitive touch as well as front-light with mono eink. This uses a layer(s) with transparent tin pattern that increases reflection, reduces panel contrast and sharpness. Having this as part of eink panel is a slight improvement compared to a separate touch panel, but not as much as claimed.
4. Next best for mono text, but far better for colour or greyscale is any emissive or transmissive screen with a special matt surface on a dark top layer (neutral density filter). A polarised top layer helps and an LCD must have one in front and behind the active panel. This is really expensive and few CRTs from the 1980s to 2010 had it. Only the best quality LCD, OLED and Plasma screens ever had it and it's rare. If the neutral density matt surface reduces light to 1/3rd then reflections from lower levels are reduced to 1/6th. The backlight (LCD), Plasma, CRT, or OLED needs to be x3 brighter compared to no filter. As with texture there is a compromise density. The coating used on CRTs, Plasma, and big LCDs originally would wear off quickly on a touch screen, so expensive micro-etched dark glass is used instead. This is very very rare on phones and tablets and quite rare on the desktop.
5. The common flat screens use polished clear glass, so no reduction of reflection from lower levels, but can be brighter. Usually set too bright. The cheap panels have the light-pipe behind an LCD illuminated with one row of LEDs at one edge giving very uneven illumination. The OLED are not real LEDs, they are electroluminescent dots with a phosphor and often a top corrective filter. Most TVs & monitors described as as LED are LCD with LED backlights. They used to use CCFL tubes. The QLED is LCD with pure blue LED backlighting and quantum dots on the LCD panel to convert (not filter) blue to red or green.
6. Finally there is Color eink. There are only two kinds for readers (Gallery is too slow). Triton uses stripes and is very dark because the 4000 approx shades and colours are saturated, so the resolution is 1/3rd in one direction. Kaleido uses a 2 x 2 pattern and the version 3.0 is very pastel to brighten it, but that reduces saturation. In the 4000+ shades, some are colour tinted. So the resolution is 1/2 in both directions. The snag is the filter has reflectance.

The only new thing about NxtPaper seems to be a more durable top layer on the glass. The next big step for it would be to use a QLED (quantum dots on LCD with blue backlight) panel for even better sunlight performance, or lower power indoors, though the charge life runs into days of use.
The Elipsa at about 227 dpi is only noticeably less sharp than the 300 dpi Sage with fine scanned text on a PDF. With a good screen orientated computer font there is little difference. But the similar colour resolution NxtPaper 11 is as sharp as the 300 dpi Sage in most cases, no doubt due to over 250 levels of grey vs 14 for greyscale anti-aliasing and sub-pixel addressing. Also the pixels on the Elipsa seem fuzzy compared to the LCD pixels, so horizontals and verticals are sharper on the LCD. OTOH, the 150 dpi of the 9.7″ Kindle DXG is poor even jail broken with a nicer font. Scanned text on a PDF is terrible. Currently only the very best color eink are as much as 150 dpi.

I don't need to buy a color eink to know it's greatly inferior to mono eink and premium LCD panels (it will beat cheap LCDs assuming you've enough ambient light). The physics is against it.
The TCL NxtPaper LCD and my particular (not any model LG) 23″ 4K HDR LG in controlled lighting beat any Apple iPad, Mac laptop or Mac monitor I've seen personally in their show room. I've also looked at €1200 second hand tablet in CEX no better than my last HD Lenovo Yoga Tab 10″ tablet (€230) which doesn't come close to my desktop LG, Samsung or QHD Benq monitors.

Mono eink has a niche future for dedicated ereaders. General purpose mono eink products are for fans. Color eink has no future unless Gallery 3 is morphed to a product with 100x faster screen update.

The non-eink refresh rates are mostly to suit video. The actual pixel response time is 0.3ms to 3ms. The very best eink is about 55ms at lower quality. Gallery 3 refresh is 1500ms!

Any flicker or tearing on modern LCDs is either too cheap back-lights or poor graphics drivers. I've even done flicker free HD video frame rate conversion by pointing a Canon EOS 70D in HD video mode (edit format, where every frame is a key frame) at the 4K HDR LG monitor.