blend4web is better than unity WebGl ?

hi every one.iam getting confusion for developing one big project (its a virtual shoping) like.that project if we develop on unity webgl,i think quality will be decrease.but in my project quality is main.ive developed some other webgl projects,in that ive faced many up and downs and too many errors and some time browsers are going to crash.Instead of that on of my friend suggested me use blend4web,its having fully quality webgl and no need any plugins to run it runs on mobile web also.But iam getting fully confusion about that,if we use blend4web we have to do more R&D for collisions layers tags rigidbodys charactercontrolling ui .....etc. on which platform is usefull to develop please tell me.sorry for my english. thanks in advance.