Your obvious rival here is PCPartPicker. Having used that extensively, here's some things I don't like about yours:<p>Expert mode removes compatibility checks. This shouldn't be the case - as soon as I select an item, it should cull the results and show me only the intersection of items that are now compatible with my chosen piece of hardware.<p>The lack of an ability to filter. Maybe I want to splurge more on a graphics card, but I need one that has at least 4 mini-display port outputs to drive my monitors. Right now there doesn't seem to be a way to say "show me only gpus that are nvidia, above $500, and can drive at least 4 monitors".<p>One of the biggest things for me: lack of reviews. You have a pangoly score. That's great and all, but you're a brand I don't (yet) trust. If I'm buying a component that costs multiple hundreds of dollars, I want more than a single score from a company I haven't heard of. I want to know what the reliability is like, and I want to hear it from people who have had hands on experience with it. I want to know how loud the fans are, what temperature it runs at passively and actively, etc.<p>Visually your site is really nice, but your expert mode leaves a lot to be desired, and I think you have a ways to go before you catch up with the competition. If I were you I would try and find your niche - either target users who are switching over from console gaming, and want to build their first computer, or build out a bunch of more expert features and target regular hobbyists.