I've just sent my buy-in chip to Tezos fundation and I will share some observation so far.
Tezos has been built with the idea that it can use any blobkchain as a lower layer and then execute distributed code on top of it to regulate smart contracts. Its unique feature is that its own protocol is subject to changes approved by stakeholders, protocol enhancements are rewarded in Tezos. Tezos is a PoS based token, so even holding it will give rewards. The main pitfall in my point ov fiew is the OCaml programming language.. which is something really specific and not very adopted. The Tezos team will use the crowdfunding also to evangelize developers about such language.
As of now, 5PM CET 1st July, 19.000 BTC and 60.000 ETH have been collected, giving the Tezos team more than enough resources already to fuel their operations. Some tips I founds while I was sending my funds:
ETH prices are more advantageous w.r.t. BTC
so if you have to buy from scratch, fixed the amount of USD or EUR, you will end up with more Tezos if you contribute via ETH (this depends on the specific rates, so double check on your exchange, of course this information varies in time)
ETH exchanges and network in general are really clogged
.. so the operation can take much more than than funding with BTC
In the end I contributed via BTC because I really don't trust much ETH network and I just had little time to go over the procedure. I will HODL for a couple of years as it's general consensus that to develop, evangelize and create some industry use cases - which are the three conditions to have a technology blooming - there will be at least 2 years of work to do.
Finally, never invest more than you can lose!