Well, I've owned both NADs and Jolidas. You don't say whether your JBLs run 8 or 4 ohm nominal, but 91 db/w is fairly efficient. Note that some tube amps can get a little flabby at the bottom as you demand more current from them. That being said, I think the final choice will depend on your listening taste and tolerance for maintenance. If you like head-banging music with mountains of controlled bass, then I guess the NAD is the way to go. On the other hand, the Jolida does a better job in presenting more palpable mids and sweeter highs. The Jolida has good bass to boot. It will also tame down a digital source better. The Jolida will also require better ventilation and periodic retubing (some cost) and rebiasing (not that big a deal). The other advantage of the Jolida is the ability to fine tune the sound by way of tube choice (and some judicious mods). For what I listen to, I found the Jolida a much more musical piece of equipment. With some select modifications, it was really no contest. Your mileage may differ, however. By the way, there's a lot more out there than NAD and Jolida, so don't necessarily limit yourself so.