I HAD a Battery Tender on mine - until one day when I decided to check the water level on the battery and noticed the sure signs of overcharging - all sorts of acidic goop had gradually built up over a few months and was piled up on top of the battery.
Now, I just don't worry about it; unless for some reason the car starts sluggishly, I'll assume the battery is good to go - and if that does happen, then I'll attach the trickle charger for a bit, until its indicator LEDs say the battery is fully charged. I also run one of the Fun Projects voltage regulator, which also helps keep the battery charged properly, I assume.