I believe that at the present time, TIPS are not a good value. TIPS are quite volatile and many people have lost money with them. This is particularly true of a TIPS fund such as the Vanguard fund VIPSX (one-year return: -2.9%). I think you want to buy the TIPS fund when the real yield is above 2.5% and sell when the real yield is below 1.5%. You can make more money off the capital gains than you can off the dividend. Presently the real yield of the TIPS fund is about 1.4%, so it is in the sell range.
If you bought a TIPS bond when they had a real yield of 3%, you should think about selling the bond and booking a nice capital gain worth maybe 2 years of dividends. Because you did so well with capital gains, you can afford to wait until the bonds are a better buy in the future.
All you have to do is chart VIPSX (tips) vs VFIIX (gnma) to see what's going on. In the spirit of full disclosure, I should point out that many people to do not agree with the buying/selling of the VIPSX as I propose here.
See also: http://research.stlouisfed.org/fred2/series/DFII10