Hi rjenk and welcome to the forums!
We are still using Motorola (formerly Symbol). We have about 8 RFS7000s, 22 WS5100s and around 1100 AP300s scattered about 7 different facilities. Our largest facilities has 4 RFS7000s with around 300 AP300s currently deployed although we are expecting to grow the AP count to around 500 within the next year. We just recently replaced our WS5000s and AP200s with RFS7000s and AP300s. We had 18 WS5000 switches in our largest facility that we were able to get down to 4 RFS7000s (the savings in rack space, cabling and power was great)
I completely agree with you concerning the management interface of the old WS5000s. It was so bad I actually wrote an application in Perl to help managed the WS5000 via SNMP. I never want to see that Java bug ridden thing again!
We have a long history with Motorola and have worked with them to resolve quite a few complex problems over the years. With that said, the Motorola product works well and is very reliable. We've also found that Motorola is very competitive with competing solutions which helps the budgeting process.
I won't knock Trapeze, it's a great solution. Motorola lacks some of the "bling" that Trapeze, Meru and Aruba bring to the table. The new WiNG software (v3.x for WS5100, v1.x for RFS7000) is a huge step forward for Motorola. It's much more manageable and has a lot of features you'd expect in an enterprise class product. As I've said we've found Motorola to be extremely competitive, I would push your Motorola rep and see just how interested they are in your business.
If you are happy with the Trapeze solution from a technical standpoint and you can fit it into your budget then I don't think you can make a mistake. You might be able to squeeze some additional points out of Trapeze by looking at Motorola.
Are you going to deploy 802.11n APs?
I believe Motorola is on the verge of announcing an 802.11n Access Port for the RFS6000, RFS7000 switches. We're looking at the possibility of going back to retro a few areas with 802.11n Access Points (AP7131) or Access Ports.
Good Luck with your decision!