You have it about right. There is additional roll resistance on grass which will shortern landing and lengthen take off particularly if the grass is longer than bowling green cut. Other things to look out for are lengthier landing runs on wet grass if normal procedure is to brake hard. Wet grass can make a great skating rink. The other, and often most noticeable is that grass strips are often far less even than hard runways and you can expect to be shaken and stirred a little.
Not a grass vs hard issue but often grass strips will be shorter than hard runways, also ofetn less well marked so this can create very different perspectives than (say) a hard runway at an international airport.
I would only advise avoidance in the case of an aircraft with take off and landing performance which is marginal on the length of runway in question or the aircraft has limited prop clearance. Otherwise caution is adequate.