Which one will be the solution to the bitcoin scalability problem (Dream of instant payments with low fees)?
Lightning Network:
off-chain protocolIt would feature a P2P system for making micropayments of digital cryptocurrency through a scale-free network of bidirectional payment channels without delegating custody of funds or trust to third parties.
[1]SegWit2x:
block size limitwas a failed contentious hardfork outlined in the New York Agreement that intended to double the block size limit. The hardfork has been denounced as an attempt made by CEOs and owners of large Bitcoin businesses to introduce changes to the currency's protocol and development cycle with ulterior motives.
[2]To me lightning network will be of good choice than segwit2mb because it is a layer two protocol that allows bitcoin users to create a network of bi-directional payment channels and perform instant off-chain transactions through these channels. Using lightning will reduce pressure on the blockchain while enabling much more transaction capacity (limited only by the number of channel open and channel close transactions that can fit in the blockchain). In terms of transaction, lightning network allowing participants to transfer money to each other without having to make all their transactions public on the blockchain (which would make transactions lightening fast).