It might help to know what your budget actually might be. However, here's my two cents:
I have both the Redington Drift (2/3) wt.) and an Orvis Battenkill (5/6) among my reels. Both are cast aluminum, click-and-pawl drag reels that offer a fairly decent bang-for-your-buck value. In my personal opinion, the Orvis is better looking, however, the drag adjustment is on the inside of this reel, as opposed to the Drift. This may matter to you. For myself, I adjusted both drags on my reels once and haven't been bothered to change them in over six years. But I prefer to palm drag a click-and-pawl reel(makes me feel more like a real fly fisherman).
I have no fishing experience with the Echo Ion, but I have handled one at the store, and I can tell you that it is a modern style, high performance reel. It features a Rulon disc drag, tight tolerances and a machined finish (it is in fact a cast aluminum reel that has been machined then coated for impact/abrasion resistance). Of the three reels you mentioned in your OP, this one is probably the best value/performance for your dollar.
Other reels you might consider:
I have a couple Okuma SLVs (3/4 wt. and 5/6) as well and will tell you unhesitatingly that this reel offers one of the best drags I've ever used. It uses a cork drag, which sounds low tech, but I can tell you that after having numerous fish over 20 inches on these reels, that the drag flat out works as smoothly if not more so than any other drag system I've ever used. They are a modern style, cast aluminum reel, large arbor design. A common complaint with these reels is that the reel foot is sometimes cast too large to fit perfectly on some rods. I had this problem with an Imperial rod. However, even though the reel foot wouldn't fully slot into the rod, it never popped off, and in no way did it interfere with my ability to cast or fish this reel.
They aren't pretty and the graphics will fade after a short time. Also, some folks say they are fragile. I've only broken one reel in the last ten years and it was one of my Okumas. I drove over it (3/4) in a 5,000 lb. SUV. The spool cracked in several places, but the reel actually survived intact. I'm still fishing this reel today with a new spool I bought for $25. So much for fragility.
I also have an Okuma Sierra (8 wt.), which I'm not terribly fond of, but it does the job I need it to do. It's another cast aluminum reel, which tends to be a bit heavy, and ugly looking, but the drag works well.
Finally, I also own a Lamson Konic (4/5). This is another cast aluminum, large arbor, disc drag reel. In my opinion, it's not as good a reel as the Echo, but if I'd never seen that Echo I probably would tell you that this one was the best of the bunch previously mentioned. As it is, while it's a lightweight, disc drag reel, which operates very smoothly, it also looks too Star Wars for me, and the finish is still obviously cast aluminum. Additionally, in most cases it's priced higher than the Echo, and there you have it.
Anyway, hope that helps. Also, you can probably do a search and find a lot more info for your questions on this subject.
Peace.
