I love Sigmund, even though I almost always use something less capable. For the price, when on sale, it's probably the most delay-bang-for-the-buck you'll find. It's routinely available on sale for ~ 55 bucks.
Echoboy is quite pricey, but last summer it could be had for 99 bucks. Maybe with Black Friday around the corner ...
You can't go wrong with Fab Filter, but sales are infrequent. Timeless 2 was actually about half price at one point, something you almost never see Fab Filter do. This was right around the time that D16 Group release Sigmund. Coincidence?
Oh yeah, you should also definitely consider Melda Production MMultiBandDelay. When on sale (it is as of today but I don't know how much longer), it's only $27 USD. Very good value at that price, IMO.