Can't leave a thread like this on a post like that, now can we?
The Urbie has its own special brand of crazy. I recommend it heartily; I own six of them (two of each variant). They are surprisingly flexible, and their low top speed doesn't hurt nearly as much as you might think it would. You have all high mounts, great hitboxes, and a very small cross-section- a combination found in precisely zero other 'Mechs (normally you get one or two and get screwed on the third). Urbie is one of the best corner and ridge peekers in its class, thanks to that combination and the Urbie's 360-degree twist, which lets it face its chassis backwards for quicker escapes into cover.
All things considered, an Urbie doesn't require any more upgrading than any other 'Mech to be effective. As with most other 'Mechs, you're going to rip the stock engine out and replace it. You're a 30-tonner, but you're buying smaller engines than you'd stick in a Locust, so that's a point in your favor.
My two most effective configs are for the R63:
UAC5 + 3xML
LPL + 2xMPL + 3xMG
If you want to put some hair on your chest, though, run a big gun... like so:
UM-R60 Super Stock
UM-R60L Boomcan
High mounts also make PPCs viable...
ERPPC + 2xML (sub a PPC if you prefer)
Alternately, there are some viable STD configs... all laserboats, though, so depending on your feelings towards Urbies without ballistics you may want to take a pass:
LPL + 3xML
2xLL (or 2xERLL if you prefer)
LPL + 2xMPL
The Urbie does have good enough hitboxes to take advantage of the dead side, but YMMV on whether or not that's a big enough bonus to sacrifice the tonnage for. The point is that it can be done, for all three variants, and save you a ton of money.
As for tactics... the Urbie was designed to fight from cover, in urban environments. It's right there in the name. The hardpoint layout makes it a superb corner and ridge peeker, so use it for that. Hide behind stuff. Pop out, take a shot, get back in cover and move to a new location. Avoid brawling in the open with it, and under
no circumstances go squirreling through the enemy team like a Cheetah. You have 360-degree torso twist... use it! If you're taking heavy fire, twist and don't stop twisting; it'll spread all the way around your torso, giving you more survivability than anybody expects out of a light (especially a slow one).
Are there better 'Mechs? Yeah, lots of them. That's not really the point. The Urbie exists to be the ultimate underdog. People either love the thing, or they hate it. You could wind up being treated as the team mascot, with other players throwing their lives away to "save Urbie!" or you might get TK'd at the start of the round. Both have happened to me. Enemies might ignore you completely, or they might go out of their way to kill you- either way, it's to your advantage; if they ignore you then you kill them, and if they hunt you then you distract them from the rest of your team.
Plus, it has probably the best cockpit of any 'Mech- refreshments on tap! Who doesn't love caffeine and laughing gas?