Seeking comments on stability of Informix on various platforms

My company is looking to make more serious commitment towards Informix, and we've got some questions before we proceed... I pushed the Informix sales people the other day on the stability of their product and they told me it's as stable on NT as on any other platform. I'm also considering Intel UNIX (whatever is most stable) or potentially Solaris/Sparc. Our experience with Informix on NT does lead us to believe that Informix is a very strong player in the RDBMS market if their UNIX software has the same reliability problems. And yes, some of this might lead to the underlying O/S vendor, but my Informix sales person isn't being very helpful in this regard right now. Right now my application is distributed across 3 4-way 2GB Pentium III servers running a primarily OLTP application against a 45GB database. This application is accessed via a web site and it needs to provide short response times for both small transactions and larger queries. Areas of concern are ability to tune I/O, or for support from the underlying hardware or O/S, in order to minimize checkpoint times. I can't seem to get them much below about 6 seconds right now. Informix consulting has come in and told us we've tuned the system reasonably well, but it wasn't clear whether the consultant really had the depth of experience to state this definitively. You can help me by providing comments in the following areas: - comparitive comments based on real world experience with these platforms. - ideas on how to identify qualified Informix DBA resources (for example Informix doesn't seem to be able to supply well trained consultants) Thanks in advance -