I learned one year of French in first year of high school, and then dropped it for German in the following year. As someone who has none of English/French/German as a first language and from an Asian background, I found learning a second or third European language using English as a medium of instruction helps my English indirectly as well. Some grammar points in English were not understood properly until I learned French from scratch.
From a comparative perspective as an outsider, I feel French have more complicated vocabularies, pronounciations are a nightmare, and puzzling gender information for nouns, but since most of the "big words" in English are borrowed from French, it means often you can make an educated guess about specific meanings of French vocabularies without using a dictionary if you know English, and its grammar is far simpler than English (no continuous or perfect tenses).
German is more complicated in overall grammar structure, but it is very logical, and compounding nouns make memorizing English vocabularies look trivial. And more importantly there are no "exceptions" in grammar that will trip you up as in English.
That was 15 years ago. I think I can recall more of my German learned than French, but living in this part of the world French is probably more useful as a tool than German (French is still a world language, while German is just a pan-European language).
Ping!
This is for sure true although German and German related languages (like Dutch, Schwitzerduetsch or Danish) are of course spoken by much more Europeans than French. French is the most important language for a westerner in Africa (as long as you do not want to learn the local languages) since France and Belgium were the most important colonial powers on the black continent.
Personally I like the very feminine (I am a real male and I like women :-)) and melodic sound of French and Italian. Maybe I feel this way because one of my first (and really sweet) girlfriends came from France and she gave learning the language a real new meaning to me. A very pleasant afterglow. Besides of that I like the classical French and Italian way of living and have spent a lot of time in both countries.
English has the advantage that it is really easy to pick up. Since it is part of the German language family Germans like me have no real problems to learn it (in difference to languages with latin or slawic origin). A easy grammar combined with a limited, but very flexible vocabulary makes it the "common denominator" for all of us. It is and will be the real "world language". Besides of that wide parts of the cultural outcome of the last century were verbalized in English. No matter if we speak about the Beatles, Freddie Mercury, Roy Lichtenstein or John Steinbeck.
Last but not least my own language, German, gives the possibility to verbalize very accurately and sharp due to its big vocabulary. Much better than i.e. in English. Although it only has its importance in the European hemisphere, it is still worth learning it.
P.S. Do you speak Mandarin if you live in Hong Kong? Do you think that Mandarin will have the chance to become also one of the "world-languages" in the west (in the far east it has this status anyway)?
French is indeed an extremely difficult language to learn, second only to Slavic languages maybe as far as European languages go. Sorry about that !
In my experience, English has been, by far, the easiest language to learn - even though it too has lots of pitfalls when it comes to pronunciation. Espagnol has roughly been on par with French in terms of difficulty, while I've always found German too logical in its grammar and pronunciation.
I play with the idea of trying to learn either Mandarin Chinese or Japanese, but that will be one hell of a challenge, I suppose !