Best solution for 2x8 index shifting I've been riding a pretty well-tuned frankenbike (I call it the argos, I've had it for 15 years) set up with claris 2x8 shifters (r2400) and dura ace (7700) derailleur on the back with an old ultegra fd.  I was using bar end shifters, but I changed to a flat bar.  I ride hard in the NYC streets for 100+ miles a week. Unfortunately, my claris shifters are terrible, slow to shift, and have a crappy feel, and I want to get something that actually shifts crisply and cleanly.  I want to keep riding 8 speed because I like it and it's durable, I have a compact cassette (13-23 w 38/52 up front, the 52 is ramped/pinned, great for city riding) that I really like riding, and my bike is set up right, but the shifters are really not giving me the performance I want.  The front shifter especially is terrible.
I know that I'm probably not going to find a top quality 2x8 set, but maybe there's a 2x9 set that I can use with a jtek shiftmate 2 to run my 2x8 bike.  Here's what I'm considering:
9 speed road:
SL-R660 (which are pretty rare, and will cost a lot) with jtek shiftmate2 (+$50) (&quot;ultegra/xt level&quot;)
8 speed mountain:
XT SL-m739 XT which will cost a lot for the rear, and I'll stick with the claris r2000 front
XT SL-m740? I think it's probably the same mechanism
XT SL-m008 (are these the same as the above?)
XTR sl-m951 which will cost ????, and I'll stick with the claris r2000 front
SRAM attack 8???
Microshift r8? (looks cheap)
9 speed mountain:
XTR SL-M970 with jtek shiftmate2 (+$50) and claris front
XT 750/760/770 with jtek shiftmate2 (+$50) and claris front
Saint 800/801/810 with jtek shiftmate2 (+$50) and claris front
I basically just want the best performing 8 speed shifter[s] and I'm willing to invest a bit (less than $200) in order to get something that is going to last (i.e.: has alloy internals, has bearings).  I'm wary of looking into current or more recent 8/9 speed flat bar shifters after my experience with claris.
I'd love to hear from people who have experience with these.
Better 8 speed shifters than exist now are pretty unlikely to start existing in the future, so any recommendation is unlikely to become obsolete.
For robustness, the hot setup is SL-BS64 shifters (the ones you already have if they're Shimano) on Paul Thumbie mounts. Loctite the heck out of the mounting screw for the shifter part. They perform great too, provided you enjoy using thumbshifters.
If you really want trigger shifters, another avenue that would produce good results is any higher end flatbar road set like the one you mention, or any left friction thumbshifter plus the best 8-speed Shimano right shifter you can find in good condition. XT, LX, and Deore have all existed, and most will be better than your Claris. (I will say that the tactile feel of the Claris set you have is of course mediocre, but they work fine, so any serious performance problems you're having with it make me suspect other problems, i.e. cable/housing friction or a slopped out RD.)
Any pre-11-speed Shimano flatbar road left shifter should work in conjunction with any 8-speed double Shimano road front derailleur. There are other things that could be causing your bad front shifting, ie weird chainring spacing or bad FD positioning. What won't work well is putting a mountain shifter on a Shimano road FD. They pull more cable. One can usually make it work by starting with a bunch of cable slack, but it's not pretty.