He wanted good games, not massively overhyped catastrophes that have aged terribly. As regards to recommendations it really depends on the type of mech game OP is interested in.

 

there's always the Armored Core games if you want something more actiony with tons of customization

 

Xenogears is one of those games released at a time when Square could do no wrong and RPG's had just hit their stride in the West. Unfortunately it is hugely flawed and had aged terribly...

One of the biggest problems is the pacing...it's immensely slow and features "quests" which are just diversionary and feel tacked on for length. Whilst not immensely wordy (it's no Trails in the Sky) it does have a fair amount of script, which isn't a bad thing if there's care and attention put into it. The story is ok...it's not some fantastic RPG high point, it's just ok and unnecessarily opaque at the beginning. What kills it though is the god awful localisation....the translation team must have been paid in peanuts (not paid peanuts, paid with peanuts) because at times it's eye bleedingly awful and if you care a jot for something being well written this is NOT the game for you. Then there's the plaforming...the exploratory controls feel "loose"...it's difficult to describe but with the isometric view and relatively poor controls it turns enforced platforming sections into at times frustrating journeys. Furthermore the mech sections are a low point...not only do they feel distinctly underpowered compared to the normal character driven combat, but they're reliant on a fuel gauge which if you're not careful you'll burn through....you also need to pay attention to upgrades or you could find yourself totally screwed as far as impassible battles. Plus as a relic of a bygone age it has a relatively stupid encounter rate...it's not SMT Persona 2, but equally it's so far from being Persona 3 it's not funny.

The characters are also not great...the main characters really fail at fleshing their story out, and whilst partly due to the terrible writing, it really detracts from having empathy with them. Then there's the old chestnut of the game being unfinished...you have an overlong first disc you'll be tiring of after about 40 or 50 hours, and then the second disc is basically 14 hours of pictures and text with about 4 battles. It's not even well written or illustrated pictures and text.

Oh and did i mention the unavoidable bug that causes a freeze if a boss you fight late on in the game uses a particular special move? If you don't finish him asap then kiss your game goodbye....

I love great RPG's....and i love well written RPG's even more. Xenogears gets a 4/10 from me...ambitious but awful.

 

Yeesh, the guy just wants mech games. Xenogears has mechs, and if he'd like it or not, just leave it at that. Well, I live for mech games, so here's some of my favorites:

Macross Triangle Frontier: An amazing game IMO, tons of content and missions, really fun gameplay, switching between three forms and fighting tons of enemies with missiles flying everywhere. Slight mech color customization, and stat upgrading. Great graphics, and there's an academy story mode, but the game is Japanese. There's a good translation guide on GameFAQs, though.

Another Century's Episode Portable: I love the ACE series, and this is like a pocket ACE3. No real story, but it's lengthy and has lots of units from many different mecha series. Good action game, and can be pretty challenging.

Armored Core: If you can get used to the controls, they're excellent PS2 ports. AC3, AC Silent Line, and AC Last Raven. Definitely some of the best mech customization games out there. AC Formula Front was made for PSP, and easier controls, but they tweaked some things and made it 1 vs. 1 only.

Gundam Assault Survive: This is practically like Macross Triangle Frontier, though it came first, and is more ground-combat based. And Gundam, of course. But their gameplay is actually very similar in a lot of ways.

Gundam vs. Gundam NEXT Plus: Great 2 vs 2 3D fighting game with tons of units to choose from, each with unique movesets.

Carnage Heart EXA: A game about programming mechs. You can also control one manually, but it's based on 3 vs. 3 mech AI battles. If you like the idea of programming automatic battle mechs, this game's incredible. It also has a visual novel story, which is pretty good.

Battle Robot Damashii: Another game with very similar gameplay to Macross TF or Gundam AS. More like Gundam AS with ground based combat, but this game has many different series like ACE, and actually, no Gundams.

Danball Senki: Not really mechs... But small mech model kits battling. Highly Japanese, however, but it has a very long story. The combat is good, though, and you can customize your small mechs with tons of parts and weapons. It's an action RPG. Go for the expansion, Danball Senki BOOST. And there's a sequel, DS W.

And honorable mentions, other mech games are Gundam Memories, Gundam AGE Cosmic Drive/Accel Universe, Kisou Ryouhei Gunhound EX, and any Super Robot Wars on PSP if you like strategy games and can deal with all the Japanese.

 

Also if you want to play Danball a team and myself are working on an English menu patch. I don't know how much (if any) of the story will be done by the time I'm aiming for the 1st release but I would like to do it.
Also I already have a Menu Patch out for Gundam AGE, again no story though.

EDIT: Don't forget that SRW A is on PSP and a few other SRW games that are translated are playable on PSP (like SRW Alpha Gaiden)