No translation is perfect
Every translation of the Bible ever produced in any language is a human production, and is not perfect. No translators have been superintended by the Holy Spirit in the way the original writers of Scripture were. The original text was inspired; translations are not. Thankfully most translations are reliable and accurate, despite their differences. The differences are not usually matters of error, but of variations in how the meaning of the original text is expressed in English.
There are some warts in the NIV11. All translations have warts, in that some portions of any translation will disappoint us. Of course, what disappoints you may not disappoint me! Some of these differences are simply matters of English phrasing. New translations and revisions usually have some infelicitous expressions that are corrected in the next revision. (See Philippians 3:10 as a possible example of this in NIV11.) These are small warts.
Most translations have a few larger ones as well. The question then becomes, How many warts are tolerable? How big are they? Where are they located? It is possible that a single translation wart, if it is large enough and ugly enough, and especially if it is located dab on the front of the translation’s nose, could be judged serious enough to cause one to look for another suitor.
The bigger warts in the NIV11 include Romans 16:1 and 2, in which Phoebe is described as a deacon—potentially problematic in some churches, but that depends on the function of deacons in a particular church. Likewise, 1 Timothy 2:12 now says that a woman is not to “assume authority over a man”—a translation that goes back to the Reformation, but one that is different from recent English translations. In Romans 16:7 we find Junia (a woman’s name) to be “outstanding among the apostles.” Most warts of this sort involve difficult issues of word meaning (1 Timothy 2:12) or textual criticism (Romans 16:7). Most have marginal notes that give alternate translations.