What chart plotters use the free NOAA charts?
BTW I have never seen a big need to run out and update my charts every time they make a change. The BOTTOM, ROCKS, LEDGES and things that matter when you hit them don't change often unless you are talking sand bars at inlets and even then there is NO chart that can be trusted...
Yes cans & nuns change constantly and no matter how up to date you think you are the big ship will come and move or replace one the next week and you're back to sq 1 all over again. No matter how out of date my charts are Basket Island Ledge is still there and has not moved for, oh, about a thousand years or more...
True, this is why I sail here with the same old Garmin chart. But, as a case in point, the same chart was wrong immediately after purchase about shoals at the entrance to Alligator River in NC (and boy did we run aground - that was one grounding I'll never forget). Stuff happens.
The laptop with chart software is a proper answer but, as you mentioned, it has in general a number of issues:
1) Getting right hardware is difficult even for a specialist (and even more difficult for a regular user). Chartplotter makers take the complexity out of hardware selection and provide a convenient package (and because they are hardware "makers", they enjoy prices that a consumer does not in general, though they don't always pass those prices on).
2) Software stability is an issue because I am yet to see anyone that ever actually dedicated a laptop just to navigation. There is always a temptation to use the laptop for many other things, install a bunch of software and in general bring it to the same condition in which an average computer finds itself (i.e. unstable and loaded with crap). Again, because users simply cannot do that to a chartplotter - plotters are "safe".
3) To compare apples to apples, it is worth remembering that a smallest laptop screen is about 12" diagonal. My chartplotter is presumably 10" diagonal and it is the largest unit Garmin sells (and about as large as plotters get). That affects both usability and power usage (after all primary power users in a computer are a display, a CPU and a hard drive when spinning). However, the numbers are not SO different. My plotter takes about 0.5-0.8 amp. My laptops (a number of different ones connected via inverter) - 1.5 - 2 amp (though it may peak a bit more on occasion). Energy use of a laptop can be easily lowered with proper hardware selection and proper power adapter.
That said, although all these problems "can be solved" clearly someone needs to do the solving because consumers are not generally willing or able to do so (and chart plotter makers are not willing to use free charts precisely because consumers will keep buying their products and then their charts)