I can't say whether they're the "best" or not, but I've used NameCheap for everything and have been extremely happy with them. Plenty of options, very good cost.
The only time I didn't use them was a weird edge case recently where I needed a multi-domain certificate, and NameCheap did not support those, so I purchased direct from GeoTrust.
The only time I didn't use them was a weird edge case recently where I needed a multi-domain certificate, and NameCheap did not support those, so I purchased direct from GeoTrust.