Don't know how well the HF version works, but, it is cheap.
The Battery Tender Jr is more expensive, but, it works.
The CTEK is one of the better ones and I like it more than the "Tender" altho I use both. The CTEK has a setting for Optima style batteries as well as others and I have found it to do better on the Optima batteries when it comes to maintaining them.
Some of the simplest float style chargers can actually overcharge a battery over a long period of time so the type that actually turn off when the battery is fully charged and then come back on periodically for a quick top off would seem to be the safest, if not the cheapest.