Sakura is great!
>>7188946RSAL, or Registered SAL, has tracking and is insured (for only up to 6000JPY, I believe), while normal SAL has neither of those things. If you're using HLJ and don't have any special need to know where your package is, just go with SAL. If you're in the US, it'll generally take about 2-4 weeks for your item to arrive (with both RSAL and SAL), but you'll get it eventually. On the off chance your item does get lost, HLJ's customer service will take care of you. Other stores, however, will explicitly say that they cannot help if a SAL package is lost, so be sure to check the store policy when shopping elsewhere.
Whenever I've used SAL it proved quite reliable. Though if it's an item that you wouldn't be able to get replaced if lost (like a discontinued item or something), you may want to go the registered route.