If you can encrypt or generate queries, then you can decrypt any order preserving encryption scheme in log_2(n) probes, regardless of the underlying data distribution.
n is the number of possible values. If you want to decrypt all caps strings, then you can decrypt the first character with log_2(26) queries, then the second with another log_2(26) queries, and so on.
If you can only observe the query stream or the disk reads, then you end up paying a constant factor more than that, but not a very large one.
Even if the attacker only has access to data at rest, if you have multiple OPE columns in a table, or if the database has foreign key relationships that link OPE data, you end up leaking all sorts of information about the underlying database.
It's hard to say anything polite about these schemes or the vendors that push them.