I have a suspension fork with lock out. You can definitely tell the difference between when the suspension is off or on, but it's not as if I'm suddenly able to fly because I've locked out the suspension. I use the suspension on unpaved trails or bumpy MUPs and I lock out the suspension the rest of the time. But sometimes I forget to lock the suspension and go quite a ways before noticing it, but then when I do notice and lock it out I can immediately tell the difference. I would probably shy away from a suspension that couldn't be locked out, especially if it's mainly for road travel. My next bike will probably have a rigid fork. For as infrequently as I unlock the suspension currently, I doubt it's worth having the suspension at all.