Recently looked at some scopes for the same reason. Sightron S111 6-24 x 50 had reasonable optics and good positive turrets and seemed good for the price. Bushnell Elite Tac 4.5-30 x 50 seemed better made, but felt quite heavy. Great optics. Slightly cheaper was the Leupold 6-18 x 40 (VX2)AO which was great for the money. Nice bright optics. For 600 I'd want something with slightly more zoom, so the Bushnell or Sightron seemed better suited to that purpose and range for me. Not a lot in it price-wise so I'd have probably opted for the Bushnell. Looked at a few Vortex scopes too, including the Viper PST (SFP). Didn't think optically that it was any better than my M18 Falcon (FFP) but was twice the price. The M18 has been doing sterling service on my .308 and was a bargain. For longer ranges though I think I'll be changing to either the Bushnell or a Leup Mk4 Tac 6.5-20 x 50. Looked at some used Nighforces but preferred the Leups and even the Bushnell.
To the OP...you haven't mentioned budget. If budget isn't a consideration, the Leup or a S&B target/tac scope should be on your wish list. If budget is an issue, the VX2 6-18x40, used Sightron S111 or a target Falcon scope all offer good value and performance. Best thing is to get to some RFDs and have a look at some.