I'll try to address this later but the companies you are talking about don't sound like they know what they are doing.

I have to try and remember what I did.

If I have a size of the venues I can get a better idea of what you need.

But rule of thumb is that if it's only for talking smaller speakers are what's needed and a lot of coverage. 10's or 12's for spoken voice, even some type of small speaker array.

So maybe the Bose system might be better even though I dislike the sound.

The proper way is to have them set up a certain distance from each other inline from the front of the stage up into the audience on a delay. that is so that the people in the back don't hear the speakers on a delay, other wise you'll hear it late or from different sources at different times like in a huge stadium. You don't want a person to hear this:

I...I...I....said...said...said...that...that...that.

If the speaker nearest you is on a delay it lets the first sound get to you and that speaker is in sync.

If there are people who are going to ask questions you need a podium or at least a mic w/stand setup in the audience. You also need to have at least one mic at the dais or podium for the speaker.

This were a compressor is really important on each mic.....people will do stupid thing because they do not know what to do with a mic. They even do it at functions like the academy awards show.

They will talk softly too far away and then talk really loud right into it....feeback!!!!

Make sure you get a list of the equipment they will be using and a diagram of the setup in a contract.

Big, reverberant halls can be a challenge to transmit spoken word. Like BD said, the echo can be a big issue. Line arrays were develped to minimize this, but modern line arrays are big $$$. You may not want to do this gig, I have no idea what your budget is. I recently got to open up a JBL line array box- their newest smallest one (#?). It had a 12" woof and (4) little plastic (and blown!) HF horns. The crossover was a HUGE PCB that covered the entire sidewall of the cabinets' interior. The list price of the box-a single one, mind you- was $2600.00!!!!! A single HF diaphragm on these little cheesey drivers was over $100 dealer cost! I'm in the wrong end of this business...
Anyway, as far as podium mics are concerned, I use the Audio-Technica AT857 (no longer made), and their replacement, the ProPoint 47 is supposed to be even better. Be careful-are you going to have to provide the actual podium as well? Most gooseneck mics come in (2) flavors-wired with an XLR that plugs into an existing connector at the base on the podium, or one with a bare-wire leads you wire in yourself. You don't want to buy the wrong one! BTW, I ALWAYS use a Sabine Phantom Mic Rider on my podium mics!!! This amazing little box uses a phantom-powered DSP in a case the size of a pack of Camels. It provides feedback control (Sabine is the best at this!), proximity/blast/pop control, and a compressor that minimizes poor mic technique AS WELL AS an infrared- detecting gate !!!! It's an automatic sound man! It works pretty well, you just have to spend a few minutes programming itto your model mic.
If the conference has PowerPoint presenters, be prepared to have a wireless onhand. That's another ball of wax.
If they're going to have a conference table with speakers (the human kind) sitting around it, you might want to have a Crown PZM on the table. Those things work decently (as long as nobody throws their paperwork on top of it or smashes it with a gavel!). Once again, I use a Sabine product (the P-Solo) to help minimze the feedback issues that accompany poor speech presenters.
The Mackie speakers are OK, but I am no longer a big fan of Mackie in general (exception-ONYX mixers). The JBL M-Pro is decent for the budget-conscious, I have a few of these. My "big rig" for the local convention centers here is a Radian system with ( 8 ) RPX112P top boxes driven by Sabine Graphi-Q EQ/time delay processors. The Radians are coaxial, so they have more intelligibilty from a compact box, and the Graphi-Q provides the time delay (that BD mentioned) and feedback control to handle reverberant rooms better. And bigger cabs are not always better in this situation.
OAP (in Atlanta area) are known for time-constant coaxial systems that are very compact and efficient in harsh areas. Don't own any, but have heard several systems of theirs that did very well in reverberant halls. You might check them out, too. Stick with Crown, QSC, or Yamaha power amps. Crest used to be good, but now they're simply repackaged Peavey. Don't wanna get me started on THAT!