There are very different inferences.
The suffix -philia comes from one of the four ancient Greek words for love. In English the suffix is used to denote love or affection. For example, an anglophile is someone who loves England or things associated with it. There are other negative uses such as paedophile.
The suffix -mania does not mean "love" - it is synonymous with obsession. In fact "mania" is defined as a "mental illness marked by periods of great excitement or euphoria, delusions, and overactivity". As a suffix, it normally denotes an obsession, such as Beatlemania - the hysterical craze for the band The Beatles that existed in the 1960s. It does not have the negative connotation of a real mental illness. In fact, it is common to say one is "crazy for" something to mean they like it enthusiastically.
A clear difference is that a "mania" may pass. Beatlemania does not exist today as it did in the 1960s. A "mania" for something tends to be a group experience that is very much "of the moment". On the other hand, someone may be labelled "an Anglophile", which suggests that their love of something is not a passing fad but something deeper.
A quick bit of research reveals that some persons today do identify as "Beatlemaniacs", but that is really a throwback to a past era of widespread interest in The Beatles that does not really exist today on the same scale. Comparing that to the term "Anglophile" - when in recent times British music or British actors have held a larger than usual place in the US music/film industry there has been no notable use of the term "Anglophilia" to describe the phenomenon. Usually some other term like "British invasion" has been coined. Again, this suggests that "philia" is more appropriate to describe a personal experience rather than a widespread feeling.
Also, I believe that "mania" may imply some action or motivation to action. Again, an "anglophile" may have an interest or respect for England without ever actually visiting it. On the other hand a pyromaniac doesn't just like fires but has a compulsion to create them.
Some words that employ these suffixes have been in use for a very long time and the reasoning behind their creation may not be documented or easily explained. I would also go so far as to say (although this is purely an opinion) that the increased familiarity with the word paedophile may put people off using the -philia suffix to describe new phenomena.
Lastly, remember that some words are created glibly, perhaps as a marketing strategy (for example Wrestlemania) or to make newspaper headlines more interesting (eg "*Britain Braces for Beiber Mania!"). So despite all of the above regarding the true meaning and origins of the two suffixes, they may not always carry the full weight you might expect.