I don't think I'd recommend a Joye 510, to be honest. I started with that e-cig, and it isn't terrible, but there are a lot of better options nowadays. The Joye's battery just doesn't have the power you need and it doesn't last. I got so sick of charging batteries all the time, I had collected 6 batteries and was buying an upgrade within a month.
If you absolutely must have an e-cig that's the size of a cigarette, there are only a few that are worth using. The best one, IMO and the opinion of most people here, is the Volt by SmokelessImage.com. It's the best of an otherwise poor performing class of e-cigs. The service is great, the
juice is good, the battery is decent and the price is fair. There is a promotion right now for something like 20% off with a coupon code that you can find around here if you ask.
Rule of thumb: The more an e-cig looks like a cigarette, the worse it performs.
If you can deal with something the size of a Sharpie marker, you'll be much better off and I'd suggest the kGo. The battery will last all day for most people. It's 1100mah, which is about 3 times the capacity of a cig-sized battery. It will accept many different
juice delivery systems and it's probably the most popular mid-sized model available for new vapers.
It uses re-fillable cartridges (cartomizers), so it's economical to use. Unlike the similar looking eGo e-cigs, the kGo is 3.7 volts, which results in a better vapor than the 3.3-3.4 volts of most eGo models.
A lot of vendors sell the kGo. This is one that has a good reputation:
KGO
There is another unit that the same site sells, called the e-Power. It is nearly identical, but it takes separate batteries. In the long run, it's more economical because when the battery wears out, you can replace it for $5 instead of buying a whole new kGo battery for $15-20