If you have a lathe with a modest centre height one of those jigs with the tall, relatively thin posts may be fine, on larger lathes though I’m not convinced by the design. I hasten to add though that the only jig I’ve used is mine and I’m happy with the design given it was made with what I had to hand. Some jigs though can be quite expensive, a German one I saw was over €600 and looked a bit fussy in design. Given the low cost I might be tempted by the eBay version. My problem is I like making tools!