Many bodybuilders have reported harder recovery when using deca, this isnt made up or internet gossip, its a known fact from many expericned bb's, there can be a few reasons why deca can contribute a hard recovery.
The decanoate ester is very long lived and can have a negative influence on recovery because even small amounts of deca can completely shut down your HPTA, if I remember right 50mgs can shut it down so expect a harder recovery when using deca because of the clearence of the ester.
Deca also has other negative influences over testosterone, deca has progestigenic properties and it binds to the PR which can act on the HPTA at reducing LH production, so deca is also contributing another factor at shutting down your HPTA and further addition to recovery.