As far as manual ones goes? I've still got my Colours Spazz as a 'just in case back up'. After about 5 years of abuse it's still in top shape. Have loaned it out to some friends that were in the process of getting their own chair and found the rentals not to fit their needs. Mine wasn't perfect for them either but a lot easier to get round with. Before that one I've had others, but those do not deserve mentioning unless we'ld open a topic on "which types/brand of chairs are cr*p".
Since end 2008/beginnin 2009 I've transferred from that one to a Colours Shockblade. Top of the bill kinda chair, nothing like it in the world. Colours is the only brand that offers a 4-point individual suspention, and actually offers multiple types of those chairs. The difference in comfort and usability between any chair without suspention and with is beyond words let alone when you get 4-point individual suspention. We decided on the Shockblade as the Boingg!! (type chair that was the first ever with this type of suspention) has one more bar on it. That bar would allow me to kinda fold my legs up in a too freaky position behind it and feel "comfy". Sure feels comfy but is so damaging with my condition that aint a smart thing. The Shockblade doesn't have that bar and thus leaves me unable to do so.
Had some other tires placed on as the "regular" options, got wheels with only 8 spokes (I kept keeping my fingers entangled and dislocated even when using protection boards etc. -part of my condition- and the less spokes or "protection", the less risk I run now) and a rubberized grip between the rim and tire itself. That not only stops me from getting my fingers entangled between wheel and rim, but it allows me to propel as I can, instead of how it "should be". I get the most "force" out of my thumbbase and now can use that by simply leaning onto that rubberized part between rim and wheel to propel.
I'm already "behind" on technology. There are so many way better gadgets out there including on making selfpropelling easier (without using any mechanicals). Can't wait to get myself some new cool things.
I'm a diehard fan of Colours. Why? Because of the options they offer and because of our national Colours dealer. That guy has the same mindset as what started this brand; "nothing is impossible, the chair needs to fit the person whatever they want to do". I can tell you, our dealer def. takes that to heart and beyond. If I need or want something that isn't "standard" (most isn't standard as it's a custom build, but you get my drift) they'll get it done. They get me whatever I want and need in a good fashion. No isn't an option. They have the same mindset as I've got and it works like a charm.
Staff of our dealer constantly tries out all kinds of new technology and gadgets themselves as half of them are 24/7 wheelchairusers themselves. The rest of them do at least one wheelchair sport, they sponsor a couple of teams so products really get tested and put through the wringer before deciding it is a good product they're willing to sell and know it upkeeps quality or they're like "not for our customers, what a cr*p". I like honesty like that, knowing they're not just in it to make a sale. If their neighbour has a better product for me, they're the first to send me back there. For me the Colours Shockblade
is the best chair and it's line has proven over and over again it can't be beat when it comes to my needs and desires. Combine that with a superb dealer and you get a fan like me.
Most important thing is that you find a chair that works for YOU. Always remember that "not possible" does not excist. Even if it isn't possible with
that chair, it is possible with
a chair. OK, they'll not magically cure you

but technology is so good nowadays you do not need to be stopped on that department. Does anything hurt? Just not feel right? Doesn't work with your way of being, living? Speak up, don't except nothing less than your perfect fit.
What kept -and always will- keep me inspired about never giving in on the "nothing is impossible" is
http://www.youtube.com/watch?v=I1SyK7RiiqY&feature=related . Folks like Aaron do backflips, go down halfpipes, you name it. Others go extreme rockclimbing and the list goes on and on. All of those things can be done with the right equipment. Technology has come so far no wheelchair has to stop any of us from doing what we'ld want to do. Money sometimes is another subject, but beyond that.................