08-09 glorys been heavy compared to other dh bikes is true but they still come in just under 20kg i think which isnt too bad at all, They are well over built too so tend to stand up to alot of abuse which is a good thing when starting.
If you can give us a price range it would greatly help in not only types of bikes. But also how you should buy (2nd hand or new)
There are benefits in buying both and your budget can have a significant effect on this choice.
As others have said The giant freeride reign tends to be a big standout for light trail/dh capable bikes, however for this price you could get a glory so this decision will come down to what riding you do and how often. When you say go back up the hill and not be fatigued, do you mean ride it back up or pushing it up? you wouldnt ride a DH bike back up a hill but the reign would be much more capable. As for control you shouldnt have any issues with controling a 20kg bike, you will find a heavier bike (within your strength) will be more stable over the rough stuff. There are still clear benefits of going lighter, personally I have found going sub 17kg for me feels too light.
If going down the reign route I would look at a 36 talas for the forks which give you 6.3/4.7 inch travel options. You want something adjustable when you decide to ride up hills.
Get up a price range in the thread and see if you can get some more detailed help.