After having both I'd stick with hank-on.
Randy, Our first boat was a 95 Hunter 26 with a CDI roller furling unit. The unit was totally trouble free and stood up very well. You will need to modify your 135 or 150 genny to fit and need to add the sun strip. It would be better to start anew. I would advise you to get a 135 with a foam luft. Without the foam the sail performs very poorly when partially furled. With the foam it will work down to about 90 to 100%.We just sold our IP 38 that had roller furling on both the 135 genny and the staysail. On bigger boats rollers are the best way to go because of the ease of use and the weight of the sails.We currently are sailing a C22 with a 150 and 110 that both are hank on sails and the ease of exchanging one for the other completely rules out a roller for us. It simply is too much fun to be able to run which ever sail is best for the conditions. Something that is very hard to do with only 1 furling sail.Either way you will still have fun, except with the money you save by not buying the furler you can get a spinnaker. Enjoy, Ray & Maria