Camping world has the Hopkins tire pressure monitoring system on sale and I was wondering if anyone would recommend that brand..If not, what would you recommend

Pressure Pro System. I got mine from Mike and Pat McFall. Good folks.

PressurePro (valve cap senders, no temperature)
and
Smartire (internal mounted senders pressure and temp)
are the industry stalwarts. Both are excellent and both have long reputations.

PressurePro is simpler - just screw on valve stem caps. I run Smartire as it also measures temperature and in so doing I might be able to detect a dragging brake on my toad before any damage occurs. Smartire is also fully programmable, I can set my alert levels (high and low by psi, not by percent) and it also pressure compensates for temperature thus ensuring I can set very tight limits w/o a temperature-pressure induced false alarm. Pressurepro uses rather wide pressure tolerances to eliminate these false alarms.

A few other brands include (I have no additional knowledge so you might do a google search and check other forums)

SAF-TTE TattleTire Pressure and Temperature Monitoring Systems F
uses valve stem caps, half the price of smarttire and does temp too as well as identify the tire location.
www.truckerspartstore.com (seems out of biz jan 2009)

another new model may be (dec2008)
Truck Systems Technologies
http://www.tsttruck.com/Product_List.html

Hopkins Systems valve stem caps
http://www.nvisionsafety.com/TPMS
Campingworld/Amazon (jan 2009)

Revolution Supply's P409-S tire pressure monitoring system reads tire pressures and temperatures
http://revolutionsupply.com
http://revolutionsupply.com/(S(etybwvapsabrlh452lsdzev0))/tpmsmonitorsystems.aspx

I suggest you to go check Kleen Wheels brand if you are looking for a good quality tire pressure check valve cap set. I have tried it before and you'll see a good performance from it.