I have both of these. The 950 sits nicely in the hand and isn't (screen wise) much smaller. The 950 is good as a daily device and battery, depending on usage, will go the day. As with all devices with multiple core chips, heat is always going to be an issue, although with use - calls texts emails and the like it's pretty good. Shut down a few background apps and it stays relatively cool. Continuum is a great toy to play with, BUT, you have to remember that it is basically a beta at the moment. It's very glitchy when wireless, and through the dock, it is markedly better. It has gotten better over time, and with OEM's jumping on board, developement of it should see something rather cool. I've used it a lot in business meetings, and many have been impressed.
The 950xl is also a very good device, if you can get past the uber conservative looks of it! It's dull, dull and dull. I guess the 950 being smaller it doesn't have the impact. I love my 950xl's. They are pretty much the same size as an old note 3. I know that because in my car, it fits perfectly into my old note 3 holder! It is weighty, but at least you know it's in your pocket. As for heat, well, there's an 8 core chip in the 950xl, and obviously, that is going to generate some serious heat when you cane it. The 950xl has some form of liquid cooling ( cool eh? ), and as a result of that, the heat is dissipated across the back of the device, not in the bottom right corner, like the icon and 930. Great in the winter. The battery, as with all devices, lasts as long as it lasts. It's a very subjective point. I use mine all day for phone stuff, as I do on my 950. Again, games and heavy weight processing will have a marked effect. Continuum on the 950xl doesn't glitch as much on a wireless system. I use mine wirelessly on a 50" Samsung tv, and it does quite well. Despite the size of the 950xl, mouse pointing using the screen is hit and miss. I've now got a B/T keyboard and mouse and things have improved dramatically.
It's personal choice which one is better. That's down to you. I use 4 of them in my company, and they haven't let me down. I will say one thing though. If you get to play with one on Threshold Release, you will probably end up asking why you had bothered. I mean it. You will wonder what is going on. Your 925 will show little difference, in smoothness etc. Put the 950 / xl on the Redstone builds, aka anniversary update, and you will be surprised. I have the insider build on a 950xl and it is pretty damned good. It unleashes the beast within, and now, to me at least, the phone makes sense. Nearly forgot. The best thing about these devices? The screens. They are brilliant.
What ever you decide, save a couple of quid, go on amazon, get a mozo cover, and jazz up the outside as well. The transform the look of the 950 and XL. Why Microsoft couldn't have added a couple of pounds to the price and provided something similar, I don't know.