Newegg

Usually very reliable. They seem to be adding many new non-computer categories via the "marketplace" style third-parties. Not sure I am a fan of this. My experience with these types is so-so at best. Seems most are Chinese based sellers who seem to exaggerate the functions and quality of their products (to put it nicely). So what if you can save 30% off on a tripod if the damn thing never works!
In regards to newegg.com themselves, they are great for any laptop or desktop computer stuff you need. I just advise being careful with the third party sellers.

Never had a problem getting my parts from them even though the shipping was sometimes a tad slower than desired. The times I've needed to make a return they always accepted valid merchandise back no questions asked.

Only issue is they're always out of stock and overpriced on new graphics cards. Hard to complain about much in my experience otherwise.

This is one of the better electronics sites out there. I ordered UPSs for work. They arrived in 2 days with the free shipping option. Awesome! Well packaged. Items just as stated.
Maybe not the cheapest but close. Barely higher than Chinese based companies. If you don't want to wait 6 weeks+ for stuff to come from China then I highly recommend Newegg.

Update: I have reviewed newegg.ca only. I cannot speak about newegg USA, Singapore, Australia, etc. I recommend that buyers look for specific reviews on those.

Have been buying from Newegg for at least 10 years. I find they have consistently good prices, a nice variety of products, quick shipping, and very little need for customer service because they get it right the first time. I've spent thousands at their site, along with others, and they currently lead the top 3 or 4 that I buy from. My experience with them spans memory, motherboards, hard drives, SSDs, power supplies, video cards, and miscellaneous boards, keyboards, mice, etc. I refurbish computers at a local community center for donation to needy families, so the need for low price and high quality is always on my mind. Good shop to do business with.

Package was lost between warehouse and supplier! Still had to wait 12 days before I could file a claim, and now am still waiting 17 days later with no progress being made on the claim and no information offered. Asking for a refund would forfeit the $78 for shipping (cause supposedly shipping was paid).

Extremely unhappy with Newegg and would recommend to use at own risk. If you see a product elsewhere, even if its $100 more, think to yourself whether the price difference is worth waiting >4 weeks for, with no guarantee of delivery at all.

Customer service is nice, if only for the fact they can stand all the dissatisfaction they are faced. They can't provide anymore information than they receive themselves. A lot of platitudes are given but do little to help in the matter.

A hacker ordered stuff from my new egg account. I was able to act quickly and cancel all items except a 99 cents gaming code. New Egg would not refund. Instead they want me to go to my bank which would result in my credit card being reissued. This is a huge unnecessary hassle given that my credit card info was not exposed. This just shows how petty and small minded New Egg is. They don't care about their customers and everything is your problem. Suffice it to say they have forever lost a customer over 99 cents. New Egg should really think about using more of Amazon's customer service practices if they want to build their business. Trust and perception are everything online. So lame to throw that away.

I bought the 5700 XT from Newegg and I was having minor problems with the card. I didn't want to take the risk of more problems so I try to return it. I heard the GPU have driver issue but bought it otherwise since some people say they didn't have any problem.It cost a big whopping $60 stocking fee for having the item for like two days. They don't even pay for shipping to send it back so you have to pay for that too. I also read that some people say Newegg didn't even accept their returns. If you do buy from Newegg, make sure you going to keep the item or else it will cost you money! Otherwise go buy somewhere else like Amazon. I return stuff from there before with no stock fee and got my full payment back!