I have Riedel Vinums and Sommelier Series as well as Speigelau Vino Grandes, ISO Expert Tasting glasses and a bunch of other Spiegeuals.
Forget about the Sommelier Series as the Bordeaux glass for example is $60+ per glass and is by far the most fragile glass I have ever used. I am literally afraid to touch them let alone wash them.
The Riedel Vinum and Spiegelau Vino Grande (the Bordeaux version) are almost exactly the same and the Spiegelau glasses are much cheaper. The Spiegelau has a thicker stem (which is better for cleaning as they are less fragile than the Vinum), a bit different base and the bottom of the bowl is a tiny bit different. Wine does seem to taste a bit better from the Vinum for some strange reason.
The Spiegelau ISO glass is great. It is sturdy and is dishwasher safe. I paid $30-35 CAD for a 6 pack ($20-25US) and they are probably even cheaper in the US.
I also have Spiegelau Riesling glasses, champagne glasses and a red wine glass that is a rip off of the Riedel extreme glass. All of them are great glasses and tend to be my everyday glass as they are relatively cheap to replace.