Hi,
I'm not going to recommend any particular set of rules, but I'll give you my "thumbnail views" of the ones I've played to any great extent.
WRG 7th (reworked as Warrior) -- Very much a "mental" game in that it often becomes more like a chess match as you figure out different matchups and try to maneuver troops so that you get the advantage. The "Barkerese" language that it is written in can spawn many heated discussions as to just what is intended. While I find it very mentally stimulating, it certainly isn't an easy rule set. A very high learning curve . . . and not always realistic.
Warhammer Ancient Battles (WAB) -- Has much more of a "skirmish" feeling than of a large "Ancients" battle. The stats/capabilities of Generals belong (if anywhere) only in fantasy -- certainly not in a serious historical game. Nevertheless, it can be fun -- but I think I'd look elsewhere for a serious set of rules (unless that's what people in your area are playing). Battlestandard Ancient Rules are certainly an improvement over these.
DBA -- Much maligned in my opinion. Simple to learn and play; but can be very competitive. Excellent as an introductory game because you don't need a lot of figures to get started. The fantasy version of these rules, "Hordes of the Things" is (in my opinion) a much better set of rules (and loads of fun -- buy it and give it a try). Good game for multi-player campaigns that can be run in a day.
DBM -- This started out as a good game -- the battles at least looked like Ancient battles. However, as Barker revised and re-revised it (and a some players became very rules lawyerish) it got worse. Not too bad if you can get a mellow opponent -- but don't play this with a "tournament player" if you want a pleasant game.
TACTICA -- I only played this a few times and found it much too formalized and constricting. Never did like it.
Battlestandard Ancient Rules -- I helped playtest these rules and our group enjoyed them very much. Something like WAB, only much better (in my opinion). I don't know how widely known they are -- nor how they stack up against some of the other rule sets others have touted (I've never even read most of them). For information, got to their website at:
http://www.battlestandard.com/rules_arm ... ules.shtml
Finally, the most useful aspect of any rule set is that someone else is willing to play it with you. Be amenable. If your opponent likes a particular rule set, play it.
Hope that this helps.
-- Jeff