Being me, I usually ignore brands and purchase the cheapest one that does the job reliably:-). Shop around. Listek and Mirror image are two popular brands. Since you already have an on-camera prompter system, maybe the next step for you is to see if you can convert it to stand-up presenter mode by just buying the floor frame, pole, and glass assembly, and using the LCD, laptop, and software you already have. Though generally, you do these kinds of gigs with two units at 45 degree angles.
There are also lectern-top mini prompters on the market, based on a netbook or ipad or whatnot, they clamp or mount somewhere near the front of the lectern like a little windshield or a rear-view mirror on a gooseneck stalk. I don’t have much faith in these, myself: the view angles are too restricted, and there is good chance the thing will throw spill light on the speaker in an unfavorable way.
The laptop and software you already have probably will work for any unit you buy. The thing to watch out for is to see if the unit you buy takes a composite video out or does it need a VGA or other format out, and can the unit manually flip-reverse the text you feed it, or must you do that part (when required) in your software?
The nice thing about old CRT based prompters is one cheap coax can feed everything with some barrel connectors and a tap. Want to add another confidence or operator monitor? No big deal. Long runs? Nyet Problem, comrade. *Maybe* you’d need a video DA for long runs or multiples, but these are like $20 at radio shack. If you need to feed multiple VGA cables out instead, this adds complexity and reduces flexibility, to my way of thinking. The cheaper LCD units will not offer hardware flipping of the signal from VGA or composite, because in essence this requiers a scan converter inside the unit at higher cost. Also, cheap units will lack an anti-glare matte coating on the LCD. Considering the vagueires of various hotel lighting setups, you’re in for some vexing situations if you don’t insist on some kind of anti-glare treatment.
One other method I feel I have to mention is ear prompting. While it costs about the same as a teleprompter, it’s invisible to an audience and the speaker can roam anywhere on stage. The system comprises a tiny hearing-aid like ear plug that picks up a radio signal from a loop antenna worn under the shirt. That antenna connects to a larger but still pocket-sized radio reciever relay, fed from someone backstage with a playback unit, or to a pocket mp3 player or digital voice recorder with a miniature, concealed remote control. Before the event, the speaker reads from a script while recording his own voice. During the event or taping, he plays it back and speaks out loud what’s in his ear. Takes a little getting used to, probably somewhat more than a mirror-based prompter, but, it has a lot of advantages too, in terms of flexibility and mobility. By reading a script phonetically, it can even enable your speaker to pretend to understand a foreign language, just by repeating word for word what he hears. The remote controls stop-start, rewind, and overall speed.