Ares ETR that I have has very nice optics. To make a substantial upgrade, you kinda have to go up in price significantly.
The first step up is probably Delta Stryker 4.5-30x56. It is not a huge step, but it is noticeable and I prefer the reticle.
To get better than that, you really have to go up to the really top end scopes like ZCO, Tangent, S&B, Minox, March, etc. If you need 25 yard parallax, I would be looking at March, ZCO and S&B. Sometimes you can find good deals on the SB 5-25x56, but reticle selection is not my favourite.
I use March 3-24x52 for its light weight and good overall quality, but parallax is not any more forgiving than Ares ETR. If weight is not a huge concern, you can always try the larger 5-40x56 March. Generally, I think Opticsplanet is closing out on their March inventory (distributor changes), so they have some good deals on whatever is in stock.
March focuses down to 10 yards like S&B. If you can live with SFP, I think Opticsplanet has one of their 10-60x56 High Master scopes for under $3k, which is not something we will see a whole lot going forward. It is sort of a different beast, but I finally had a chance to look at their High Master glass a bit more carefully and I am kinda impressed. As it trickles over to their FFP designs, we will see some interesting things, I hope.
ILya