Nothing is completely perfect; there must be some flaws in everything.
1. Accounts are totally free, however!, to open an account you have to buy a certain amount of “RAM”, so that you can create the account and register it on the network. And this is a little expensive and could cost more than 1$. **This shall be resolved soon and completely so that it will be 100% free via "vRAM", and after implementing the parallel processing update.
2. Operations are completely free, however!, In order to execute operations, you need to allocate a number of your EOS tokens, to be able to use the network bandwidth and the processing (NET/CPU). This is also a little expensive. Even if you can do a few operations, you have to allocate more than 1 EOS, which might be inconvenient for some. **This will be fully resolved after the implementation of vCPU, and vNET, and after the implementation of parallel processing, and multi-thread.
3. There is a usage daily limit, if you consume it completely, you may not be able to carry out any processes until 24 hours later. **This could be good to preserve the network strength and avoid spamming the network.
4. from the announcement of ICO, until the network launch; one of the objectives of EOS is to enable filing a lawsuit at a body called "ECAF", to recover stolen Wallets and Tokens; also to freeze the thieves accounts, but there was a flaw in the organization of this matter, and the appointment of the appropriate people for it. The ECAF was shut down and so far there is no complete solution for this matter, current dialogues are being held to arrive at a suitable solution.
5. Many did not like the launching of the network, which was delayed several days; and was considered chaotic, but they did not know that the network does not fully function before the vote of 15% of the token holders; and this was one of the reasons for the delay, also the network launch was decentralized, Which means there is no particular entity behind it, what happened that several networks were launched at the same time, and the majority of the audience adopted one of it.
6. EOS network is Centralized! Many people like to describe EOS as centralized blockchain because of its reliance on 21-121 Block Producers, who are spread around the world. In fact, block producers are extremely similar to the mining pools; such as those in Bitcoin and Ethereum. The mining pools are servers, that are selected by Those with large mining power. Similarly, block producers are also selected by the EOS token holders, by voting, and they could be changed at any time. They are safer for the network, than the miners whom their personal interest comes before the network interest, as a whole and the owners of the currencies in general. those who have a greater mining power would control the network and the interests of the primary network owners, who are the holders of the currency. Also, the mining pools with the largest mining power in Bitcoin and Ethereum are not more than 7 pools only; while EOS has 21 main block producers and 121 standby producers, so which is more decentralized ?!