I consider myself a moderate scope junkie. While I can't afford the best scopes, I like to outfit my finest airguns with the finest glass I can. Earlier this year I started using reading glasses as my once perfect vision is starting to fail. It should be noted that ALL of my scopes are FFP. So that affects my opinion on the reticles below.
Most of my airguns run the Hawke Frontier or Sidewinder range. I think they are good scopes that don't break the bank. The clarity is good, the reticles are good, the turrets are... ok (so I primarily use them with hold-over), and the eye boxes are quite forgiving. I've also owned a variety of Athlon scopes. They offer a good bang for your buck. The upper end (like the Cronus) is an excellent scope that closely compares to the Element Nexus & Nightforce NX-8 scopes, though the Cronus is quite a bit larger. A few years ago I ran the Midas Tac on several airguns. While its a good all around scope, my failing eyes simply couldn't get along with the ultra fine reticles.
I tried the G1 Titan scope and did not like it. It was a beast of a scope, and even though it boasted relatively high magnification, it wasn't really usable and gave me an instant headache. I find that most mediocre scopes are best utilized under 75% magnification. I've yet to try the Element Helix, but I've read good things about the price point vs quality & features.
My best airguns run the Nexus G1 & G2, and the NightForce NX-8's. So I will compare these for you:
Regarding the glass of the Nexus G1 & G2 I can't tell any difference. They are both really good, and the edge to edge clarity is outstanding even at maximum magnification. The illumination is great (red only) and there is no bleeding on either model. The G2 does offer more magnification, and superior turrets and controls. The parallax on these scopes demands more precision, and the eye box is pretty tight at the highest magnifications. The reticles are crisp, though a bit on the thinner side. For my eyes this is a non-issue (so long as the eye bell is properly focussed). The G1 is selling at a great price and is a great scope, but the G2 is simply better.
The NX-8's also have great edge to edge clarity throughout the magnification range. The illumination is great (red & green) and there is no bleeding. The turrets have a great tactile feel, better than the Nexus G1, but not as good as the Nexus G2. The parallax and the eye box on these scopes are more forgiving. The reticles are crisp, though a bit on the thicker side.
The older I get the more selective I get with my optics. When I shoot I typically spends hours behind the glass. If a scope isn't easy to use, doesn't make me happy, or gives me a headache, you'll probably see it in the Classified section
-Michael