Around here, the regular concentration Tide products have all but disappeared! However, Wisk and Purex liquids are still available in regular concentration formulas.
I think in general, the Tide and Gain HE products work the best.
After that, comes Wisk, and then Purex.
Kirkland HE liquid from Costco is a quality product found at Costco at a very reasonable price, but I do not recommend it. It is an extremely sudsy detergent.
I've also experimented with a good detergent....Arm & Hammer with Fabric Softener powder in both TLs and FLs and, really, it is such a low sudser, so inexpensive, and a good product, that IMHO it should be designated an HE product! The only thing to consider is that I remember launderess and other posters here warning that Arm and Hammer powders have high levels of washing soda (makes sense) as an ingredient, and that some posters here believe that could be detrimental to the innards of your washer.
Most of the other interesting liquids that perform well do so with more suds in my soft water than I am comfortable with.