Should the PinYin of "我不如你忙。 Wǒ bù rú nǐ máng。" more correctly be "Wǒ bùrú nǐ máng." ?

我的汉语不如你的汉语棒。
Wǒde hànyǔ bùrú nǐde hànyǔ bàng。

My Chinese is not as good as your Chinese.

Rosetta Stone displays this pinyin:

Wǒ de hàn yǔ bù rú nǐ de hàn yǔ bàng。

I like to keep the particles separate so I would write it this way:

Wǒ de hànyǔ bùrú nǐ de hànyǔ bàng。

Now, here is an online textbook that you might find useful:

http://ocw.mit.edu/resources/res-21f-003-learning-chinese-a-foundation-course-in-mandarin-spring-2011/online-textbook/

Here is what they say about Pinyin conventions:

6 Writing connected text in pinyin

Unlike earlier systems of Chinese phonetic notation, some of which were intended as fully fledged auxiliary writing systems that could co-exist with (or even replace) characters, pinyin was intended as an adjunct to characters, used to indicate pronunciation and to provide a means for alphabetical ordering. For this reason, the rules and conventions for writing connected text in pinyin were not well defined at first. However increasing use of computers for the production of text and in everyday communication, as well as the proliferation of contact between China and the rest of the world has put a premium on the use of pinyin. Nowadays, in addition to its use in pedagogical materials such as this book, pinyin is used for emailing, for input in word processing, for url or email addresses, and to complement characters on advertisements, announcements, and menus, particularly those intended for an international audience in Chinese cities and abroad.

In 1988, the State Language Commission issued a document with the translated title of “The Basic Rules for Hanyu Pinyin Orthography,” and with a few minor exceptions, this textbook conforms to those proposed rules. [The ABC Chinese-English Dictionary, cited at the end of the Background chapter, contains a translation of this document as an appendix.] Only two general points will be mentioned here. First, normal punctuation practices hold. Sentences begin with capital letters, as do proper names; they end with periods, and other punctuation marks are used more or less as in English. Second, words, not syllables, are enclosed by spaces. Thus ‘teacher’ is written lǎoshī, not lǎo shī. Characters, by contrast, which always represent syllable-length units, are separated by a space regardless of word boundaries. Of course, defining what a word is can be problematical, but pinyin dictionaries or glossaries can be relied upon to make those decisions for us. Other conventions, such as the use of the hyphen, will be noted when needed. So when you write pinyin, it should look like this:

Gémìng bú shì qǐngkè chīfàn….
revolution not be invite-guests eat-meal
Revolution isn’t [like] inviting guests over for a meal….
Mao Zedong

Writing pinyin in this way makes it readable. And in fact, where emailing in characters is restricted by technical problems, pinyin can serve even without tone marks so long as the above orthographical conventions are observed: Geming bu shi qingke chifan…. 

欢迎

谢谢，
再见，
大卫