I started shopping at Wally's back in the early 80's. I still stop in from time to time...I've been to every pet shop around the area and Wally's has decent but not the best prices on tanks. Besides tanks, prices seem really high especially when compared to online shops. Some high as 70%. PetSmart matches their online store prices, so I print out what I need and purchase it locally.
I will say, Wally's is step above Annandale Super Pets. Now there is a owner that has no clue. I wouldn't spend a penny in that place. Tom on the other hand is a nice guy and has fair amount of knowledge, but can use a little brushing up when it comes to reef setup.
Wally's staffs are less than friendly, give very poor advice and need product knowledge. About 6 months ago, I asked, how long will it take to set up a reef tank? One of the staff member said, with all these modern technology and advance chemistry, few days. Went on pointing out what I would need...I lost him at "few days". Needless to say, I ended up in Herndon and dealt with a small pet shop owner and ordered $2000 worth of stuff including Oceanic tank and stand. He wasn't that knowledgeable, but he was honest and very helpful.
I would still stop in from time to time, but I seriously doubt I would purchase much.
Online shops offer great prices and fast shipping. There are many pet stores around the area that I don't mind purchasing from. I've been around so much and so often, I know who has what and know their prices. Example, Tropic Marine "Pro" Sea Salt is about $15 lower than Wally's Tropic Marine Sea Salt...and they are much more knowledgeable and friendly. Smile goes a long way.
This is just my experience and honest opinion.