This is my first grow so I can't really compare to HPS/MH but I love the LEDs I did a lot of research and found that Prosource seemed to be the best so I purchased one, the LED I have is rated to do this entire plant on it's own, I added the CFLS as supplemental lighting. Obviously I have been pretty successful with the LED/CFL combo.
As far as it being common for plants to grow so wide, it is very strain independent, each one will grow differently, there re many training trechniques available though to get the plant to grow how you want it to, on this grow I did not use any of those techniques and opted for a natural approach. Just my personal choice as it is my first grow.
The benefits of the tent: I mainly bought this for temp control, the LED I use suggests a temperature of 85º my closet was running between 90º-94ºF which any temp above 90º slows or stops growth, so I need it a little cooler, the tent was able to make this happen for me. Also the reflective coating is much more reflective of light than the white painted walls in my closet. Keep in mind if you are going to cut clones those clones will grow quickly and need to be in a room of their own under veg lights i.e. 24 hours cycle while your other plant is still flowering on 12/12 The tent gave me the added convenience of having 2 rooms, which is now necessary for the setup I have as the 8 clones are in veg and the mother is flowering.
Good luck to you and welcome to the forum. I'm glad you liked my journal, please do not mistake me for a pro or anything though as this is my first grow and even though I'm successful I'm still learning and all my info might not be the best to follow haha. There are a lot of great people on this forum that are willing to help, I suggest starting a grow journal, even if you are still in the planning stages maybe get some ideas going.
***edit*** Also i should mention those CFLs are very powerful lights so I am thinking having them as side lighting really helped contribute to the plant becoming so wide.