It might help if you posted what features you're most interested in and what prices you've found on the 2 receivers, as well as how experienced you are with calibrating a reciever, and what speakers you'll be driving.
I have the 45tx and like it very much. I especially like the self-calibration feature, quality of the processing, and ease of use of both the receiver and the remote. It's not recommended if you'll be driving 4 ohm speakers, and I think it may be more costly than the Outlaw if you buy at a local B&M, though it can be had for $800ish online. I don't have any experience with the Outlaw, though I know that model has lots of very happy owners, so you wouldn't be going wrong with one.
Hopefully someone who's tried both models will chime in with some information and comments.
I can get the 950 for $899 and the 45tx for about $804. I have been setting up home theater for about 10 years, so no problems there. I have the 959 on the 30 day demo plan right now and I am looking for a good pre-amp to go with my Parasound 855. I am looking for good clean sound in HT and good sound for Music. I do more HT in my Dedicated HT then music. I currently have the 6.1 set-up. Want to know how the Pioneer compares to the 950 sound wise.
I've got a 45tx but am not using external amplification. I love the way it sounds, but have not listened to the 950/amp combination so can't give a valid opinion as to which sounds best.
There are several fairly long threads on the AVS Forum about the 45tx, with postings from several people that are using them as pre-pros, but I don't recall any from folks who've also used a 950.
I am a 45tx owner and I do enjoy it for the Home Theater experience. However, I do not listen to 2 channel material through the 45. I have dedicated equipment for that purpose.
If two channel is important to you, I would look at the 45tx and a nice integrated amp with HT bypass. Maximum bang or the buck in a dual propose system. A decent dedicated 2 channel pre amp will outperform the 950.
BTW, I got my 45tx from an authorized dealer for under $850 shipped. email me for details...