I had the same dilemma when I got rid of the Maguras for XT v's, in the end I opted for the standard SD7's.
For me the extra money for the SL's was not worth it for the amount of weight saved, if I was going for a lightweight build or money was no object then I'd reconsider the SL's or probably go for KCNC or something like that.
The standard SD7's are great levers though and not exactly heavy themselves, although the dial itself is a bit gimmicky IMO as once I adjusted it I've never touched it since.
CRC are doing SD7's for £18 a pair, can't complain at that price, and the SL's are double the price at £35, I honestly don't think they are any better, just lighter by maybe 30g or so.
_________________Bikes... 1993 Orange Prestige, 2016 Boardman FS team.RIP...[url=http://www.retrobike.co.uk/forum/viewtopic.php?f=6&t=301709]1988 Tushingham B52,1988 Stumpjumper Team, 1991 Scott Pro-Evolution,1992 Kirk Revolution, 1993 Klein Attitude HLF, 1994 Univega Alpina 5.7,1994 Dyna-Tech Diablo, 1997 Pace RC200 F6,1997 Proflex 857,1998 Kona Lava Dome, '01 GT i-drive 5.0, 09' Orange P7, 09' GT Chucker, 2013 Planet-X Pro Carbon, 2013 Ghost ASX.