Merkur HD open comb v closed

I have probably a stupid question so please bear with me. I am looking at buying a HD. What is the difference between the "open comb" HD and a normal one? What are the benefits and which one suits what kind of beard?
Which one do most people think is better?

Thanks

I used to have both but gave the open comb model away. The OC is very good IMO if you're not shaving daily: it's an outstanding tool for shaving a few days of stubble growth. For daily shaving, it was a bit harsh for my skin.

The safety bar (regular) model is a very fine all-rounder of a razor. Forgiving yet aggressive enough. highly recommended. You'll find this is one of the most recommended razors on this board.

Thanks for the info Stauff.

I had both in the classic handle version. The OC was an inferior razor. There is almost no gap between the comb teeth and the blade making a close shave nearly impossible. I don't understand why many market the OC as a heavy beard/aggressive razor - it isn't.