Yes, You can rely on ethereum as one of your altcoin for a long investment. Placing as secondary to bitcoin is quite achievement and many ICO's now are sponsoring ethereum as payment for all campaigns that they are promoting. This is the reason why myetherwallet site becomes famous because most ICO's sponsors are recommending this wallet for ethereum payment. For your referrence just check day to day coin value thru coinmarketcap.com this site will give you an accurate movement of ethereum and other coins. good luck