Is APower Conditioner For A Mostly Vintage System Worth Getting?

I've used a Furman Elite 15i for several years and been very happy with it. Seven outlets, six on the back and one on the front, line filtering, surge protection, front panel voltage readout. 
I use it with both SS and tube amps and have never noticed any current issues with either compared to plugging straight into the wall. 
https://www.crutchfield.com/p_756ELTE15I/Furman-Elite-15i-7-outlet-Edition.html?tp=568&awkw=4349...

If you don't want surge protection or filtering I'd agree with the Wiremold recommendation.

+1 on the Furman Elite 15i.  Just got a used one last month for $115 in as-new condition.  Nice piece of gear!  There's one on Ebay for $99 right now that I'm looking at for the bedroom system!

Generally a power conditioner will allow greater clarity. Tighten the bass a little From wolly loose, to clean, precise. The down side may be the sound get leaner than it was. 
Generally trade offs. A power strip is only as good as the cord going to it. 14 gauge can allow 15 amps to pass, though the plug will probably be heating up..The main thing is how good are the outlets in the power strip? Many cheap ones are just two strips of cheap copper passing below the openings for your plugs. I would say make your own. You can buy Pass & Seymour heavy duty duplex for $6 each. a couple of hardware Electrical duplex boxes for two duplex or three. and wire and a plug.The nice thing about making your own, is you can upgrade the parts if you want. I just stuck some Furutech duplex in my Menard's source duplex pair boxes, removing the Pass & Seymour Duplex I used for many many years. I use them besides my two power conditioners.. Good Wattgate plus are like $13 each. I still use them too. I have Magnepan 20.7 speakers, a Conrad Johnson ACT2 preamp.. not cheap stuff, but i used the Pass & Seymour duplex for years and years.

Save your money as this is not a high end high resolution system.Enjoy!!