I manage a couple of hundred Linux servers, most of which are HP, if they are not virtualized. Historically, we have installed the HP ProLiant Support Pack (PSP) since before I started working here. The PSP comes with usefull (?) stuff like the HP System Management Homepage - which I have never used, but a couple of my colleagues do regularly - and a bunch of drivers.
Some of these drivers, like the iLO kernel module, are not in the stock kernel we use, so it might be useful to install those. Other drivers though, like the cciss and qla2xxx drivers HP supplies, aren't that useful: they are in the stock kernel and have been for quite some time. Overwriting the stock drivers will probably void support from our vendor on several kernel subsystems of not the whole kernel. On the other hand, HP might not support certain issues if you do not use their drivers.
I tend to lean to not installing the HP drivers, but what do you think: is there a tempting reason to install HPs cciss, qla2xxx, e1000, tg3, bnx2 (etc.) drivers and overwriting the drivers provided in the stock kernel package?
Edit: 'tempting reason to install' must be big enough to mitigate the disgusting quality of the packages of the PSP, meaning I have to repackage them all manually in order to be able to install through a centralized method like RH Satellite.