Good LED generally isn't cheap, flexible self adhesive LED ribbon sells for between $40-$80 per metre (5 metre rolls). For the top of the line stuff, it runs at about 10-12watts per lineal metre, but with a light output comparable to a 1200mm 36w fluro tube, or better - it's pretty impressive stuff. You can even get strip now that is both dimmable and adjustable colour rendering between cool white and warm white (as well as the full colour changing LED that's been around for a while). We use the LED strip so much these days it's as common in a commercial interior fitout as a downlight.
But horses for courses, if you're happy with the strips you bought I hope they serve you well, for $5 you really have nothing to lose. If you have them running straight from an unregulated supply (ie car battery) they might not last too long as the cheap stuff usually doesn'y have very good electronics, but hey just get another set for $5!!.
The good thing about the massive leaps forward in high quality LED technology means that even the cheap chinese stuff is vastly better than what it was, as the advances do filter down. The main thing I don't like though about the cheap LED is that the quality of the light and the colour rendering is pretty poor (either too blue, or too yellow).
Bit of a tip for everyone, if you're buying any LED products online, without getting into the specifics, if you go for something with fewer actual LED's, with a yellow dot in the centre of the LED, then they will drastically outperform any of the products with lots of small LED's. EG: if you compare a torch with 20 tiny LED's, and a torch with one 3w or 6w Cree LED, the CREE will blow it out of the water every time.
another thing to remember if wiring up multiple LED strips, make sure you don't connect too many strips in a daisy-chain fashion (feed in one end, and out the other end to the next strip etc). Wiring them in this way means that all of the total load of the circuit will be flowing through the individiual conductors of all strips cascading, and generally (especially with cheap LED) the conductors within the strip are not meant to carry any more load than that individual strip. Best way to go is to loop your feed into one end of each strip only, so your cables are taking all of the load and not the LED strip conductors. If you want a wiring diagram (if my description is a bit confusing...) let me know, happy to draw one up for you.
