The most that can be said about these bonds is that if you (a) reach out on the maturity spectrum, (b) hold the TIPS for the full duration and (c) hold them inside a tax-deferred account like an IRA, then you will have a positive return.
The relative performance or RS analysis confirmed the new highs in early 2012, but has since dropped below its WMA.The RS line has important support at line c, which needs to hold on a further correction.