One thing I don't like about OCaml is that I always find myself writing the same things, like "to_string" functions for my variant types (although there must be some ways to alleviate this burden). Also, when your programs use abstract data types you lose the benefits of pattern matching. In that case, I'm happier with languages like Go or Ada with a friendlier syntax.
If you have an ADT but want pattern matching, try Scott Encoding.
For instance, here we have Option
module Option = struct
let scott (some : 'a -> 'r)
(none : 'r)
(opt : 'a option) =
match opt with
| Some a -> some a
| None -> none
end
module LL : sig
type 'a t
val fold : ('a -> 'r -> 'r) -> 'r -> ('a t -> 'r)
val scott : ('a -> 'a t -> 'r) -> 'r -> ('a t -> 'r)
end = struct
type 'a t = Cons of 'a * 'a t | Nil
let rec fold cons nil = function
| Cons (h, t) -> cons h (fold cons nil t)
| Nil -> nil
let scott cons nil = function
| Cons (h, t) -> cons h t
| Nil -> nil
end