I really enjoy my portable ice maker, it's the small kind they sell at most big box stores (I bought mine at Sam's Club)
Doesn't use much electricity, I use it even when boondocking off grid... nothing better than sipping on an icy drink when it's 90°F outside.
If the water going in is warm, the ice maker struggles for a while. I usually let it run for an hour or two with the basket out, so it recycles the ice right away. After it gets the water cooled down, the ice it makes is hard enough to crunch on but without busting a tooth.