The SD may appear a little sharper due to the 544x480 resolution vs EA's 480x480. Certain WA HD channels may appear clearer than EA channels as well due to the 6 9-channel (and 1 10-channel) transponders on EA vs only 3 9-channel TPs (no 10-channel) on WA.
I suppose the SD may be subjective due to some people preferring the slightly higher res on WA and others preferring the MPEG4 on EA which has less compression artifacts. As for HD, well, for the most part that's true, with the exception being the TPs with 9 and 10 HD channels.
As for signal strength EA has "lower" values due to 8PSK FEC. Though sat 129 on WA is also 8PSK, and it's signal strengths are comparable to EA. For example, 72.7's minimum threshold is around 46-50 (depending on the TP) and 129 is around 47-50 in my area. All of the TPs that have HD on 110 are also 8PSK and will exhibit "lower" signal strengths that are comparable to EA. One example TP would be TP 07. Just as 129 has a single CONUS QPSK TP (TP 21) which would be comparable ("higher" strength) to most TPs on 110 and 119. For example, on almost all TPs on 129 I get 56-62 signal strength whereas on TP 21 I get 75-78, comparable to most of 110's TPs being 75-78.
Once 110/119 move over to 8PSK (when they get rid of legacy receivers) then the signal strengths on all sats on both EA and WA will be comparable. Regardless, they are still similar in strength regardless of the Point Dish indications. As long as you are above the minimum thresholds, you're good. Also, I'm sure you know this, but signal strength doesn't make any difference in PQ. You either have a picture, or you don't. There is a very fine line in-between in which it pixelates, though, but it's major pixelation, not subtle PQ differences.