Excellent write-up of the four bikes on my current shortlist, over roads I've just come back from - we did the Outer Hebrides loop Oban-Barra-Eriskay-South Uist-Benbecula-North Uist-Berneray-Harris-Lewis-Ullapool and then spent a few days knocking around Assynt on the same roads you took. Absolutely fantastic trip and I can also heartily recommend the roads and scenery on the outer islands.