Hello,
SIM is free Insight Control isn't, so if you only want to monitor your hardware SIM would be my first choice.
SIM can be downloaded from http://h20564.www2.hp.com/hpsc/doc/public/display?docId=emr_na-c04271436
Insight Control adds OS deployment VM manangement etc, so if you already have that the choice is easy.
Insight Control is a suite SIM is just hardware monitoring, that is you can also montor the up/down events from othet things like virtuals etc. You can also do basic cluster monitoring and diskspace but that's about it.
SIM and Insight Control have been replaced by HP by Oneview but that suite is more like Insight Control, if you just need the haredware monitoring i would recomend SIM.
Insight Control prices can be found here : http://h30094.www3.hp.com/searchresults.aspx?mfg_partno=BD883A,C6N31A,T9101ABE,C6N38AAE,C6N38A,C6N28AAE,C6N27A&jumpid=in_r3924_insightcontrol_vplazaola_heasmith