I have to agree with most other people here with Symphony X and one thing is for sure, you won't find the vocalist "bad." In fact, though I also have many years under my belt (18) as a guitarist as well, one of SXs few weaknesses is that they DO have such a great vocalist but Romeo (guitarist/orchestral programmer/songwriter) doesn't write so many songs that really show off his vocalists' talent. Trust me when I say the vocalist, Russell Allen is that good.
Many of the faster songs Romeo writes basically sounds like old Yngwie (Yngwie's attempt at rythm) but there are some gems like Accolade II, The Odyssee and many others. SX is still a neo-classical band, but they have moved quite a bit into a more of a prog format without really losing the NC style and it has served them well.
I can only assume you own Yngwie albums. If not, Yngwie Malmsteen's Rising Force, Marching Out and Odyssee are must have's. Odyssee had Joe Lynn Turner on vocals which created a more "accessible" or poppy Yngwie sound, but song writing and over-all quality didn't suffer and in fact, improved. JLT and YM were tailored for each other and should have put out more than the one studio release (there is aslo a live release with JLT on vox)
If you are looking for GREAT guitar go back to 80's German metal. Wolff Hoffmann of Accept was a heavily influenced by classical and although the band was far and away from Neo-Classical, the Metal Heart - Russian Roulette era Accept had some of the best guitar work I have ever heard. The same goes for the 80's Scorpions. Because they had a good bit of commercial success, they were a bit overlooked by guitarists, but I'll argue with anyone until I'm blue in the face about Mattias Jabs over Micheal Schenker. If I could phrase like Jabs, I would never put my guitar down. I can't think of anyone better.
I realize these last two are not close to neo-classical, but if you aren't familiar with these two Teutonic Supermen Hoffman and Jabs, I think you will be impressed by there precision, combination of styles, phrasing and production as both bands were produced by Dieter Dirks who is known to "hide" extra guitar tracks and riffs in the production and is a guitar oriented producer.
Bryant