The O's snatched a draw late on through Dean Cox but had made much of the running throughout the match, even taking an early lead through Romain Vincelot against a strong QPR side.
Despite concerns over the fitness of defender Scott Cuthbert, Slade said he was happy with his side's latest run out.
He told the O's website: "It was a really good workout, I've been pleased with all the pre-season games and the benefit they've been to the group. This has been no different.
"I thought we showed some passages of real quality against a top side. It was good experience and more minutes for us.
"We passed the ball well, managed the game quite well at times and kept the ball."
On Cuthbert he added: "He's got an injury. It's a thigh injury and we're going to have to have a look again and maybe scan it and see where it takes him."
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