Has Anyone Used a Link Building Service That Actually Delivered Results?

I’ve been looking into link building services to boost my client site’s SEO, but I’m skeptical about the quality and results. There are so many options out there, and I’ve heard mixed reviews—some say it’s a game-changer, while others call it a waste of money. Has anyone here used a link building service that actually improved your rankings or traffic? If so: * Which service did you use? * What was the pricing like? * Did you see long-term benefits, or was it just a short-term boost? Any advice or recommendations would be super helpful! Thanks in advance.