Madeira's most beautiful routes tend to already be covered by MIUT or one of the many vertical-kilometer races, so this was a less trafficked way to cross the island from (South) sea to (North) sea. Only the early levada section and the start of the trail right after you top out (Bica de Cana) are popular for hikers.
The route is a mix of road, concrete/dirt levadas, dirt track, and a bit of mushier surfaces in the middle of the route. It's largely easy to follow.
Backtracked a few times, wasting effort but not more than 3 minutes total .. walked behind levada hikers through the route's only cave (at approx 4.4km/2.7mi) .. and in the agonizing last mile before hitting the road on which you crest the top of the route, walked verrrrrry gently past several groups of cows on a pretty darn narrow path. Terrifying! Apart from that, a lot of "jogwalking" on the uphill.
Note that the route is at times totally exposed to the sun - yet when you go around a bend, you're completely shaded by the hills. Same is true of the wind and fog as you progress uphill. Be prepared - bring clothing appropriate to the changes between hot, cold, dry, humid, etc. In regards to footing - some areas are never totally dry so expect mud, water, and slippery rocks, in addition to dry gravel/rock/sand and roads. Special callout - moss is slippery whether wet or dry. Use caution on the entire second half of the route (downhill).
Specific to today:
It was sunny and 21C/70F today (in early January). Felt hotter in the exposed areas. Got a good sweat on within minutes as it's quite a sharp uphill start :-)
Food/water - Unsupported. Brought a few gels and 1250ml fluids, finishing most of it. Underfueled a bit in the last 7 miles as by that point it's a steep downhill and i needed to stay focused on the ground/terrain instead of fussing around with my pack.
Noticed a couple of public taps in the first ~1.5miles when you are climbing up and away from Ribeira Brava beach, if you haven't come with full bottles and/or want to cool yourself off in the heat.