You might want to step up to a custom combat 4006 from the Performance Center like the 40 Recon. I have an excellent one for sale in the classifieds. Check it out.

I had a sigma 40E and liked it. It comes with night sights as standard and the grip area is checkered. The slide is rounded on the top. They used to go for around $250 - 350.

I stumbled across a 40E (New in the box)in my travels. If you're interested, send me an email.

I bought a 4006 in 1996 and carried it for years. Excellent gun but heavy, invest in a good belt and holster and maybe a shoulder rig for winter. I carried mine in a Galco jackass rig in the winter.
I have recently switched over to M&P 40 and love it, love it, love it.

my 4006 fully loaded weighs 2 lbs 14 oz
my 40ve fully loaded weighs 2 lbs 0 oz
the final decision is up to you all of the choices you are looking at are all good choices

Personally I carry my 4006 more than I do my 40ve but im a bigger framed guy at 6ft 1in and about 230 so I can hide the bigger weapons a little better than most. No matter what route you go all Smith & Wesson weapons are Guaranteed for life