Both guns are about equal in performance, both are extremely accurate, but the R-11 has that Rekord trigger. In case you've never handled a TX, its a BIG gun. Just under 10 pounds without a scope, its about equal to the RWS 54. The R11 at a bit over 8 pounds is a bit easier to shoot off hand, but its looong. I have the R-10 in .177, which is basically the same action with an adjustable stock and sleeved barrel. Its shoots 930 or so, 850+- with 10.5gr heavy pellets. The R-11 should be close to that out of the box.
If you're upping the ante from 250 to nearer 600 $$$, and are willing to deal with a 10 lb gun, the RWS 54 is something to look at also. Its at least as powerfull as the others, maybe a bit more. Its as accurate as the others, and is recoilless, unlike the others. My 54 is in .22, shoots well over 800, and will drill squirrels easily at 70+ yards. It doesn't have the fancy adjustable stock or Rekord trigger, but its built like a Tiger tank.
I've got a whole cabinet full of guns of every size, weight and power.The powerful guns look and feel impressive, and make a good show for those who've never seen them in action. However, I find that the heavy howitzers tend to stay in the closet more than the light ones when its time to defend the feeders. You really don't need 900+ fps for picking starlings and squirrels off the birdfeeder, especially if its not more than 20 or 30 yards away. A 45" 10 pound gun is a bit unwieldy when trying to nail a squirrel from the window or rushing a shot on a starling. These big powerhouses need slow deliberate aiming, and a bit of effort is involved. I find that a small light gun is much preferable. I use my 12fpe .22 Xocet more than anything lately. Its just the right size (39", 8 lbs with scope), its light, quick, easy to shoot, and very very accurate. I can easily shoot 3/8" or smaller groups at 30 yards with it. In .22 its shooting Silverbears at 670 or so, more than enough for squirrels.
On another note, you might want to look for a used FWB124. Theres one on Brads classifieds, a nice one too.
http://www.airguns.net/classifieds/classifieds_body.htmlI have 2, another due in a day or so. This is the gun that defined the sporting air rifle. The 124 has a reputation of almost mythical proportions, and a large following among both shooters and collectors. Its about the best quality spring gun around. The 124 is .177 only. Of the 2 I have, one shoots at about 820, one at about 930. Factory guns shoot about 800 give or take. What is remarkable is that cocking effort is on the order of 20 lbs or less. Even if the gun needs a spring or seal its absolutely worth it. There plenty of upgrades available- springs, seals, stocks, triggers etc should you decide to go that way.
But then again, theres always that nice R-9 Deluxe...