Best Tonearm Lifter?

  Yes, the tru-lift is worth it. Works like a charm. 

Tried both Tru-Lift and Little Fwend.  IMO, the Little Fwend (LF) is better built and was less hassle to install.  Had issues with tuning the Tru-Lift to trigger- tighten/loosen.  In my case, the LF had a slightly smaller footprint (diameter of base) and worked better.  Purchased for $249 at Music Direct.

Have had the Douk Audio tone arm life for 6 months now. The are about the least expensive at $87 with shipping from China. Works fine seems well built. 

Will Douk Audio tonearm lifter work on a VPI prime turntable?

I bought my first Audio-Technica Safety Raiser(AT-6006 ) in 1980, for $19.98. It worked flawlessly, for over 30 years. Then, something apparently dried out and it began lifting more abruptly. I found two NOS/NIB pieces, on eBay, and bought both. Well worth the money, even at nearly six times the original price(each). It now appears to have been re-released, by AT(the AT6006R). From the outward appearance; the Douk is a Chinese knock-off. https://www.ebay.com/itm/Douk-Audio-Automatic-Tonearm-Lifter-Arm-Lift-For-LP-Turntable-Disc-Vinyl-Re... and here’s the new one, from AT: https://www.audio-technica.com/cms/accessories/398e4995e9bfe926/index.html It seems both companies have eliminated the lock-down/lift-defeat wire, of the original(not a big loss). ie: https://www.vinylengine.com/library/audio-technica/at6006-safety-raiser.shtml  Any of the three, would have plenty of room, between the arm mount and platter of a VPI Prime table.