When comparing GameDev Market vs Unity Asset Store, the Slant community recommends Unity Asset Store for most people. In the question“What are the best sources of royalty free game assets?” Unity Asset Store is ranked 2nd while GameDev Market is ranked 6th. The most important reason people chose Unity Asset Store is:
Those who have downloaded an asset can give it a rating (5-star system) and optionally a written review. Packages with at least four show their average rating, and total number of ratings. (Packages below the threshold show "Not enough ratings" instead.)
Ranked in these QuestionsQuestion Ranking
Pros
Pro Offers a good variety of resource types
GameDev Market includes 2D, 3D, UI, and audio resources.
Pro User review system helps gauge asset quality
Those who have downloaded an asset can give it a rating (5-star system) and optionally a written review. Packages with at least four show their average rating, and total number of ratings. (Packages below the threshold show "Not enough ratings" instead.)
Pro Excellent presentation, organization, and search
The Unity Asset Store is well-presented, with an intuitive category system and effective search. In addition, the requirements to place an asset on the store include providing several standardized graphical and descriptive elements so that individual packages match the same presentation standards as the store itself.
Cons
Con Personal storefronts could have better discoverability
Currently personal storefronts / seller profiles have a simple list of assets. There are no categories, tags, genre-information, type information, etc that could help narrow the list down.
Con Basic search
Search only matches keywords with titles. No way to search based on type, color, etc.
Con Unity3D license required to download assets
Though assets may be browsed through the web, they can only be downloaded from within a licensed and registered copy of Unity3D (Free or Pro). However, once downloaded, the Asset Store EULA does not prevent using them in non-Unity projects so long as those projects match the "games and interactive media" description.