Jews for Jesus is unique in its spelling of the Hebrew word for Jesus. They spell it "Y'shua" instead of "Yeshua."
I first encountered the unique spelling of the word "Y'shua" in the book title "Y'shua: The Jewish Way to Say Jesus," written by Moishe Rosen. I will not comment on the CHUTZPA of such a title. I see three key affronts in this spelling.
First, an affront to the Hebrew Language. The name Yeshua, which appears in the Biblical text in the 2nd temple period (The high priest Yeshua ben Yehozadak, mentioned in Ezra 3:2, 10, 18 e.g., appears as Yehoshua in Haggai and Zechariah; similarly, Yehoshua [Joshua] ben Nun is called Yeshua in Neh. 8:17). The standard transliteration of the name in English translations (including the JPS) is Jeshua (retaining the German J, pronounced Y, as in Jerusalem [Yerushalayim]). Since JPS can arguably be considered more of a standard of Jewish usage than JFJ, we would be more fair in saying that "Jeshua" is 'the Jewish way to say Jesus.' Obviously, the substitution of Y for J would better convey the original pronunciation for today's English readers.
Second, it is an affront to accepted standards of Hebrew transliteration. The Yod in Yeshua is vocalized with a Tsere, a vowel which is usually long, sometimes short, but never "ultra-short" as an apostrophe in transliteration might imply. Even the ultra-short sheva, which vocalizes the Yod in "Jerusalem" and "Jericho," is typically rendered by an ultra-short e (as in the English word "believe," unless you come from the deep south).
Third, it is an affront to the English language which requires a vowel following Y if the Y is to be pronounced as a consonant. Without a vowel, the Y itself takes on a vowel function, typically pronounced as a long E, as in "Yves St. Laurent" and "yquem" (pronounced "ee-quem") a "fine, rich sweet white wine", or as a short i, as in "Yggdrasil" (pronounced "ig-drasil"), "the ash tree which, in Scandinavian mythology, binds earth, heaven, and hell." Hence, Y'shua should be pronounced as "EE-Shua," as in "Como estan Paco y Shua?"
Drash: A brief linguistic evaluation indicates that, in fact, the spelling of the name Y'shua actually throws new and important light on Jesus' true identity. Of course we know that in Hebrew the Yod and Vav are often interchangeable depending on their position in the word. When the root Yalad ("give birth") is cast in the passive (niphal) form, the yod is replaced by a vav, vocalized as a vowel (long o), "nolad." Similarly, the Y' in Y'shua, since it must be pronounced as a vowel, may actually represent a long o sound and hence should be written O'.
Turning to the second element of the name, we note that in the Greek transliteration of the Messiah's personal name in the New Testament, an upsilson represents the u of Y'shua. It is well known that the actual pronunciation of the upsilon, even in the second temple period, was a long e sound--hence the second part of the name would be written "shea" (similarly, note that another form of Joshua's name (Yehoshua) was Hoshea (Deut. 32:44)).
Putting the two elements of the name together, we see that the name should actually have been written "O'Shea"--indicating that Jesus was not in fact Norwegian but Irish!