Personal preference, but I find half clips to be the worst of both worlds. You have to flip the pedal over to get into them and then they offer pretty much no retention. They do offer some reference to locate your foot in the same position and alignment, but that is about it.

Also one of the advantages of clipless or clips and straps with the straps cinched is that you can extend the power stroke by pulling back on the pedal at the bottom of the stroke. Half clips offer none of that.

On the plus side you don't have a strap making exit more difficult or cutting off circulation in your foot. So if all you want is something to consistently locate your foot they may make sense.

My personal take is this:
Clipless is my first choice by a long shot. Clips and straps or bare pedals are kind of tied in second place, but distant enough that I am unlikely to ever opt for them on a long tour. I do use bare pedals around home for short errands. Half clips are an extremely distant third, distant enough that I wouldn't consider them myself.