Haven't heard about HUDCO yet. I'm not sure but this time govt. allowed only roads and power based organisations for tax free issuances - So people like HUDCO and NHB might not come. Btw, IREDA should fetch you equivalent of HUDCO - both being AA.
I invested in the first and third tax free issuance, the experience has been very good - as i booked 10-20% capital gains (apart from usual interest) across the various series and moved for better opportunities.
It is difficult to imagine such out-performance at current yields unless G-sec/repo rate goes down drastically.