I want to extend a wi-fi signal to an unattached building the farthest distance would be 90’. When I read reviews online it seems that they all have good and horrendous reviews. Anyone had great luck with a particular brand or model? A powerline network extender was suggested by the tech support guy for my current ‘bricked’ extender, then I would plug the range extended into the powerline extender.
We went to Fry’s and asked several different sales folks for recommendations and selected the one that fit our specific needs (well under what you need). I recommend checking Fry’s - the local store has knowledgeable employees in the section that sells computer “guts.”
We use them within our single story house. We have wifi plug ins good for laptops and those plugged in for the desktops to give good service to the router elsewhere in the house. Bought online- not everyone has the Frys stores in their area. I wonder- if the buildings are connected electrically this would be different than if on separate circuits- being able to use the system we use for the desktops. For pure wifi use you need to think about where in the primary building the router is located. Can you install a second router on the same account in that other building?
The reason I recommended a physical store is that (a) if the person is not a geek, most online descriptions will sound like they are written in Greek and (b) even if we recommend something, the designs and models of electronic gadgets change much quicker than those of household appliances, so anything that was awesome 3 months ago will be either unavailable or obsolete. 
Returns of electronics can be tricky, so if I were to buy something online, I’d check Costco and the reviews there.
We have one here, and I installed one at my mother’s house, which is vary rambling, due to the connection of a formerly separate cottage. Both plug into an outlet, both work fine.
Frankly, I don’t understand some of what you said in your post! “Bricked extender”? But one thing I would consider before doing anything else is reevaluating the performance of your wireless router. You might want a stronger one instead of or in addition to an extender.
I’m thinking Crutchfield, we are not near Fryes, but Crutchfield offers stellar C/S, even after the purchase and ships quickly. I had been looking at Costco and the reviews before I posted, it’s like the stuff on Amazon with 9000 5 star reviews, but the 90 1 star reviews all mention really believable issues.
I had my daughter buy one and set it up for me. Works great. I couldn’t tell you the make or model. I figure it’s a generational thing. The young people just seem to have an intuitive feel for digital gadgets that I can’t begin to touch. Probably how people who grew up with the horse and buggy felt when the automobile came in.
We bought this set from Eero, based on one of those “Best Tech Gifts” reviews on the radio one year:
https://www.amazon.com/eero-Home-WiFi-System-Pack/dp/B00XEW3YD6
I don’t know if it would work well for your situation or not. We set up 3 units to expand the range and strength of our WiFi in our 1800 square ft. home. It’s an old home, with plaster walls and lots of rooms (vs. big expansive open space).
It solved the problem we were having with weak signals in parts of the house.
Good luck!
Eero works somewhat differently from a range extender and is expensive. To extend wifi signal 90’ out one probably needs 2-3 eeros. Major $$$$. One eero covers 1,000 sft, so about 30 ft out max.
Placement of your modem/router is also important. It’s best to place your modem/router closest to your unattached bldg yet able to provide full coverage to your own home and set up an extender able to pick up a strong signal from your modem/router and provide coverage to the other bldg. You may need 2 extenders if one is not enough and purchase a more powerful modem/router.
Have you considered using bigger antennas on your current wireless router to get more antenna gain. You should easily be able to go 90’.
I bought a Peplink Pepwave Surf SOHO MK3 Router (SUS-SOHO-T) for my vacation home that uses WiFi with 802.11ac as WAN where I can have the WAN, which is normally cable or FIOS be instead a WiFI link to an Xfinty hotspot. The router had 3 antennas which I replaced with these
https://www.amazon.com/gp/product/B00DMJI9TA/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
Though we use a closer one, the router can pick up a hot spot over a mile away across a lake, though at a low rate. It took about 10 minutes to set this whole thing up.
Having a router with 802.11ac is important because it has better multiple antenna tricks that extend the range.
Interesting, the Crutchfield guy also recommended the Eero, and I like the antenna idea, too. Currently we have teh cable modem sending out the wi-fi, with no antenna. I’ll take a look at these ideas.
Wifi WPA2 encryption on many devices is vulnerable to a type of replay attack called KRACK. Watch for software upgrades on your devices. Meanwhile, ensure that anything sent over wifi is additionally encrypted (e.g. use https not http).
We have Netgear equipment in our 2 story house. Extender is placed at the base of the stairs to the 2nd floor. Works very well.
I just bought a Netgear Orbi system (similar to eero) for our house. It was super simple to set up, and I get great wifi connectivity in all rooms of the house now. No more dead spots, anywhere. But it is pricey.