Since the roll-out of Belle FP1 for Nokia 603, 700 and 701, users have been reporting issues with X-plore in the updated OS (crashes and hangs). Considering this, lonelycatgames released a new version of X-plore recently (18th April). The new X-plore 1.58 is mainly released as a bug-fixed Nokia Belle FP1 compatible version. Rests of the features and functions are same as in older version.
X-plore is a very useful Symbian file manager with an impressive feature-set (refer to this post to know about its features in detail). In fact it is a must have app for power users (Symbian modders and hackers) as the built-in Symbian file manager has many restrictions. While hacking Symbian phones, X-plore is required to access system folders (for example to copy hacked installserver inside C:/sys/bin).
You can download X-plore free from here (trial version but with full functionality and no expiration).