Aw Man, why do you have to ask a question like that....
Buy Both...
No here's the low down
The RAH is newer and was filmed in Hi-Def, however it is a standard def disc. It's a 1 disc package, with some bonus features, the only draw back is that its only Uncompressed Stereo Sound. Other notes, it's the pulse-like stage design, and features, 4 backing vocalists, 2 of which perform great gig, Also features Cattell on vocals, along with Wilson, Darlington and maybe Smac. and has an unforgetable guest appearance by Humphries. It's a best of and features some tracks (i.e. - pigs, set the controls), not found on the Liverpool/DSOTM Disc
Now for the Liverpool/DSOTM disc, It is a longer cut of the show, featuring all of DSOTM, plus 1 1/2 hours of hits. It comes with 2 discs, 1 - concert 1 - bonus, the bonus disc has loads of features, and hidden gems as well. The concert was shot in Standard Def, however it has both a Stereo and 5.1 Surround mix (give or take a center channel).
Both are well worth the money, and if you can find me, maybe I'll sign it, and you can sell each on ebay for $26.
decisions, decisions.
Have a great time at the show!!!
PS you can buy pulse on dvd now, only bummer is its 4:3 (unfortunately thats how they shot it.), both TAPFS dvd's are thankfully 16:9