Writing a Series of Equalities and Inequalities across Several Lines

Question

What is the convention for writing a series of successive equalities and inequalities across multiple lines? Let me explain. Let $E_k$ denote an expression; for example, $E_0$ could be a sum or an integral. So we write some thing like: \begin{equation} E_0 \le E_1 = E_2 < E_3 = E_4 \end{equation} If $E_k$'s are large expressions, what is the generally accepted way of writing this across several lines?

1. \begin{align*} E_0 &\le E_1 \\ &\le E_2 \\ &< E_3 \\ &< E_4 \end{align*}
2. \begin{align*} E_0 &\le E_1 \\ &= E_2 \\ &< E_3 \\ &= E_4 \end{align*}
3. \begin{align*} E_0 &\le E_1 \\ &\quad = E_2 \\ &< E_3 \\ &\quad = E_4 \end{align*} or something else?