What's the sense of how lightning network is performing? I realize that we are still very early in the deployment of Lightning network, but is there a sense of how things have been performing thus far? Is this the solution which BTC has been waiting for? I'm hoping to get a sense from anyone who is well knowledgeable about the project's development.
Yes, as of writing, there is an overwhelmingly positive sense of how things are performing thus far - more than 800 nodes with 1600 channels are already on the main net, and micro transactions exchanged more than ~40.000 USD. 
It is unclear what you mean by "the solution which BTC has been waiting for". Who is BTC? The community, using bitcoins?

The solution can be SEGWIT, Lightning, SCHNORR sigs, Smart contracts ... ??

Maybe you talk about blocksize, or the fee peak problem in December, which has been discussed in several channels, with many politics involved. This peak has meanwhile reduced to normal values, and doesn't exist anymore (see here). There is also a common sense, that with future lightning adoption this will not re-occur. 

I want to stress the point, that lightning is on mainnet, but at a very, very early stage. It is not recommended to be used by newbies, it is more for experts to see behaviour in real world (after extensive tests in test environments).