Yes, computer radios, radios with model memories, can save the settings for each plane. The Spektrum line has a unique feature in that it will not let you accidentially fly a plane with the wrong model selcted in the radio. The other brands lack this feature. While not absolutely necessary it can help avoid crashes due to having the wrong model selected in your radio.
Since you mentioned the DX6i, let me suggest that maynot be your bestchoice.Not because it is not a good radio but because Ithink it isnot as good a value when compared to the DX7s.
Now, I am looking at standard packages. Your dealer may have discounts or other packages.
Also be sure that the receivers in the packages are appropriate for your planes. Spektrum makes a range of receivers. They have receivers that are primarilysuitable for indoor flying.Then they have short range receivers that are good for about 1000 feet, sometimes called parkflyer receivers.And they make full range receivers thatare good for over a mile. If that DX6i you looked at is a "micro lite" package, that is a short range receiver system.
DX6i - includes 1 full range receiver - $209
DX7s packaged with 3 receivers - $299
1 eightchannel full range, 1 four channel full range, and one 6 channel short range receiver (good for about 1000 feet)http://www.horizonhobby.com/products...s-md2-SPM7800C
So, you wll notice that the DX6i package is cheaper.But if you look at thevalue of the include receiver, $80, the net price of the radio is $129.
The Spektrum DX7s comes with 3 receivers, totalvalue is about$200. That makes this much more capable radio about $100, or about $30 cheaperthan the DX6i.And it isloaded with feature. You might not careabout them today,however youcould easily find you want them tomorrow. If you get the DX6i, you will bebuyinganother radio. With the DX7s that is less likely to happen.
The Spektrum 7s provides more channels, more features, more model memories and a telemetry option. It also provides for on-line software/firmware updates.
If the DX6i needs a software/firmware update you have to mail it back to Horizon Hobby. The DX7s can be mailed in too, or you can just download the updates from your home computer.
If you arefocused on basic aircraft, parkflyers, .40 to .60 class 4 channel glow planes and not likely to get into large or complex birds, that DX6i may be adequate. However the DX7s will broaden the range of models open to you and it does it at an attractive price.
You have to judge for yourself but I think theDX7s is a MUCHbetter buy!
If you want to talkabout servos, this thread might be helpful.
Let’s Talk about Servos