Not sure which Er you had a look through Sauer but mine is this one
Leica ER 2.5-10x42 BR Ballistic Reticle with BDC 50004 for sale! - EuroOptic.com
The reticle is quite thin much more so than say a Leupy VX3 on 10x, not quite as a P4L fein on 12, and to my eye the glass holds with the S&B all the way to dusk.
The only thing I'm not keen on is the clicks are a little close together and moa but it's not a dialer anyway.
Second focal but that's not really an issue as it's on a simple hunting rifle
Not sure but a guy at Euro optic a couple of years ago told me the only difference with the i model was the illumination, I haven't seen an ERi so cannot confirm.
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